Cystic Tumor of the Atrioventricular Node: Difference between revisions
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{{CMG}}; {{AE}} {{MC}} | {{CMG}}; {{AE}} {{MC}} | ||
{{SK}} Mesothelioma of the | {{SK}}Mesothelioma of the AV node, AV node tumor | ||
==Overview== | ==Overview== | ||
Cystic tumor of the atrioventricular (AV) node is a [[rare]] [[benign]] [[congenital]] [[tumor]]. The [[origin]] of the cystic tumor of the AV node is still controversial. Although it is called [[mesothelioma]] of the AV node, it appears to have [[Endoderm|endodermal]] origin. The size of the [[tumor]] ranges from 0.5 mm to 30 mm and size of the tumor is not correlated with the occurrence of [[fatal]] [[arrhythmias]]. On [[gross pathology]], small multiocular [[Cyst|cysts]] are characteristic findings of the cystic tumor of the AV node. On [[microscopic examination]], [[solid]] [[cell]] nests and [[cystic]] structures lined by flattended [[Cuboidal epithelium|cuboidal]] and [[squamous epithelium]] mixed with rare [[neuroendocrine cells]] ([[C cells]]) are characteristic findings of the cystic tumor of the AV node. The [[immunohistochemical staining]] of the cystic tumor of the AV node is in favor of the [[epithelial]] [[differentiation]] of the tumor. Cystic tumor of the AV node is most commonly [[Diagnose|diagnosed]] [[postmortem]] in individuals died due to [[sudden cardiac death]]. [[Fatal arrhythmias]] including [[ventricular tachycardia]] or [[ventricular fibrillation]] may occur despite [[pacemaker]] placement. Only a few cases of cystic tumor of the AV node has been [[Diagnose|diagnosed]] antemortem. [[Imaging]] modalities including [[echocardiography]] and [[MRI]] are helpful in making the diagnosis. [[Histopathological]] [[examination]] of the [[Resection|resected]] [[tumor]] provides the definitive [[diagnosis]]. Because of the critical location of the [[tumor]] and its unfavorable [[prognosis]], [[Surgery|surgical]] [[excision]] is the mainstay of treatment for cystic tumor of the AV node. [[Anti-arrhythmic medications|Anti-arrhythmic drugs]] and lifelong [[pacemaker]] placement may be necessary after [[excision]] to manage any post-[[Surgery|surgical]] [[AV block]]. | |||
==Historical Perspective== | ==Historical Perspective== | ||
Cystic tumor of the atrioventricular (AV) node was first reported by Armstrong and Mönckeberg in 1911. <ref name="Armstrong">{{cite journal| author= Armstrong H, Mönckeberg JG | title= Herzblock, bedingt durch primären Herztumor, bei einem 5 jährigen Kinde. | journal= Dtsch Arch Klin Med | year= 1911 | volume= 102 | issue= | pages= 144-146 | }} </ref> | Cystic tumor of the [[atrioventricular (AV) node]] was first reported by Armstrong and Mönckeberg in 1911. <ref name="Armstrong">{{cite journal| author= Armstrong H, Mönckeberg JG | title= Herzblock, bedingt durch primären Herztumor, bei einem 5 jährigen Kinde. | journal= Dtsch Arch Klin Med | year= 1911 | volume= 102 | issue= | pages= 144-146 | }} </ref> | ||
==Classification== | ==Classification== | ||
There is no established system for the | There is no established system for the [[Cancer staging|staging]] of the cystic tumor of the [[AV node]]. | ||
==Pathophysiology== | |||
The cystic tumor of the AV node is a [[benign]] [[Congenital disorder|congenital]] [[tumor]]. Although it is also called [[mesothelioma]] of the [[AV node,]] it appears to be a misnomer. The [[origin]] of the cystic tumor of the AV node is still controversial. It is believed that it has [[Endoderm|endodermal]] [[origin]], derived from [[congenital]] rests during [[embryogenesis]]. <ref name="pmid2222148">{{cite journal| author=Burke AP, Anderson PG, Virmani R, James TN, Herrera GA, Ceballos R| title=Tumor of the atrioventricular nodal region. A clinical and immunohistochemical study. | journal=Arch Pathol Lab Med | year= 1990 | volume= 114 | issue= 10 | pages= 1057-62 | pmid=2222148 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2222148 }} </ref> <ref name="pmid21043810">{{cite journal| author=Cameselle-Teijeiro J, Santías RR, Nallib IA, Forteza J, Barreiro NA| title=Cystic tumor of the atrioventricular node: a rare cardiac pseudoneoplastic lesion. | journal=Arch Pathol Lab Med | year= 2010 | volume= 134 | issue= 11 | pages= 1584-6 | pmid=21043810 | doi=10.1043/2010-0268-LER.1 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21043810 }} </ref> One study suggested that cystic tumor of the AV node and [[solid]] [[Cell (biology)|cell]] nests of the [[thyroid]] have similar structures and may share the same [[developmental]] process; therefore it is assumed that cystic tumor of the AV node is an [[Ultimobranchial body|ultimobranchial]] [[Heterotopia (medicine)|heterotopia]]. <ref name="pmid15716232">{{cite journal| author=Cameselle-Teijeiro J, Abdulkader I, Soares P, Alfonsín-Barreiro N, Moldes-Boullosa J, Sobrinho-Simões M| title=Cystic tumor of the atrioventricular node of the heart appears to be the heart equivalent of the solid cell nests (ultimobranchial rests) of the thyroid. | journal=Am J Clin Pathol | year= 2005 | volume= 123 | issue= 3 | pages= 369-75 | pmid=15716232 | doi=10.1309/GWT2-PY0T-77PB-BA1A | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15716232 }} </ref> | |||
The | On [[gross pathology]], small [[multiocular]] [[Cyst|cysts]] are characteristic findings of the cystic tumor of the [[AV node]]. The [[tumor]] may be invisible from the [[endocardial]] surface of the [[heart]]. Therefore, [[Section|sectioning]] through the infero-[[medial]] [[tricuspid]] annulus might be required. <ref name="pmid26838113">{{cite journal| author=Miller DV| title=Cardiac Tumors. | journal=Surg Pathol Clin | year= 2012 | volume= 5 | issue= 2 | pages= 453-83 | pmid=26838113 | doi=10.1016/j.path.2012.04.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26838113 }} </ref> <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> The size of the [[tumor]] ranges from 0.5 mm to 30 mm and the size of the [[tumor]] is not correlated with the occurrence of fatal [[arrhythmias]]. <ref name="pmid19237400">{{cite journal |vauthors=Guo J, Zuo S, Lin C, Ji Y |title=Surgical treatment of a giant cystic tumor of the atrioventricular nodal region |journal=Interact Cardiovasc Thorac Surg |volume=8 |issue=5 |pages=592–3 |date=May 2009 |pmid=19237400 |doi=10.1510/icvts.2008.191866 |url=}}</ref> | ||
On [[microscopic]] [[histopathological]] [[analysis]], [[solid]] [[cell]] nests and [[cystic]] structures [[Line|lined]] by flattened [[cuboidal]] or [[squamous]] [[epithelium]] mixed with rare [[neuroendocrine cells]] ([[C cells]]) are characteristic findings of the cystic tumor of the AV node. <ref name="pmid26838113">{{cite journal| author=Miller DV| title=Cardiac Tumors. | journal=Surg Pathol Clin | year= 2012 | volume= 5 | issue= 2 | pages= 453-83 | pmid=26838113 | doi=10.1016/j.path.2012.04.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26838113 }} </ref> <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> <ref name="pmid10722558">{{cite journal| author=Paniagua JR, Sadaba JR, Davidson LA, Munsch CM| title=Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery. | journal=Heart | year= 2000 | volume= 83 | issue= 4 | pages= E6 | pmid=10722558 | doi=10.1136/heart.83.4.e6 | pmc=1729374 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10722558 }} </ref> | |||
On [[immunohistochemical staining]], the main [[Tumor cell|tumor cells]] [[stain]] positive for: <ref name="pmid9832064">{{cite journal| author=Arai T, Kurashima C, Wada S, Chida K, Ohkawa S| title=Histological evidence for cell proliferation activity in cystic tumor (endodermal heterotopia) of the atrioventricular node. | journal=Pathol Int | year= 1998 | volume= 48 | issue= 11 | pages= 917-23 | pmid=9832064 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9832064 }} </ref> | |||
*[[Cytokeratin]] [[CAM]]5.2 | |||
*[[Cytokeratin]] AE1/AE3 | |||
*[[Cytokeratin]] 34βE12 | |||
*[[Cytokeratin]] 5/6 (CK5/6) | |||
*[[Cytokeratin]] 7 (CK7) | |||
*[[Epithelial]] [[membrane]] [[antigen]] (EMA) | |||
*[[Carcinoembryonic antigen]] ([[CEA]]) | |||
*Carbohydrate antigen ([[CA-19-9|CA]])19.9 | |||
* p63 | |||
*[[bcl2]] | |||
*[[Galectin-3]] | |||
== | The [[neuroendocrine cells]] of the [[lesion]] [[stain]] positive for: <ref name="pmid16254122">{{cite journal| author=Evans CA, Suvarna SK| title=Cystic atrioventricular node tumour: not a mesothelioma. | journal=J Clin Pathol | year= 2005 | volume= 58 | issue= 11 | pages= 1232 | pmid=16254122 | doi= | pmc=1770778 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16254122 }} </ref> <ref name="pmid10722558">{{cite journal| author=Paniagua JR, Sadaba JR, Davidson LA, Munsch CM| title=Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery. | journal=Heart | year= 2000 | volume= 83 | issue= 4 | pages= E6 | pmid=10722558 | doi=10.1136/heart.83.4.e6 | pmc=1729374 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10722558 }} </ref> <ref name="pmid9832064">{{cite journal| author=Arai T, Kurashima C, Wada S, Chida K, Ohkawa S| title=Histological evidence for cell proliferation activity in cystic tumor (endodermal heterotopia) of the atrioventricular node. | journal=Pathol Int | year= 1998 | volume= 48 | issue= 11 | pages= 917-23 | pmid=9832064 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9832064 }} </ref> | ||
*[[CAM|CAM5.2]] | |||
* Pan-[[keratin]] (AE1/AE3) | |||
*[[CEA]] | |||
*[[Calcitonin]] | |||
*[[Chromogranin]] | |||
*[[Synaptophysin]] | |||
* hyroid [[Transcription]] Factor 1 (TTF1) | |||
[ | The [[tumor]] [[Stain|stains]] negative for: <ref name="pmid16254122">{{cite journal| author=Evans CA, Suvarna SK| title=Cystic atrioventricular node tumour: not a mesothelioma. | journal=J Clin Pathol | year= 2005 | volume= 58 | issue= 11 | pages= 1232 | pmid=16254122 | doi= | pmc=1770778 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16254122 }} </ref> <ref name="pmid10722558">{{cite journal| author=Paniagua JR, Sadaba JR, Davidson LA, Munsch CM| title=Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery. | journal=Heart | year= 2000 | volume= 83 | issue= 4 | pages= E6 | pmid=10722558 | doi=10.1136/heart.83.4.e6 | pmc=1729374 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10722558 }} </ref> <ref name="pmid9832064">{{cite journal| author=Arai T, Kurashima C, Wada S, Chida K, Ohkawa S| title=Histological evidence for cell proliferation activity in cystic tumor (endodermal heterotopia) of the atrioventricular node. | journal=Pathol Int | year= 1998 | volume= 48 | issue= 11 | pages= 917-23 | pmid=9832064 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9832064 }} </ref> | ||
*[[Keratin]] 20 (CK20) | |||
*[[p53]] | |||
*[[Bcl-2]] | |||
*[[Cyclin D1]] | |||
*[[Cytokeratin]] 20 (CK20) | |||
*[[Vimentin]] | |||
*[[CD31]] | |||
*[[Factor VIII]] related [[antigen]] | |||
*[[Estrogen receptor]] | |||
*[[Progesterone receptor]] | |||
*[[Thrombomodulin]] | |||
*[[Wilm's tumor|Wilm’s tumor]] 1 | |||
*[[Calretinin]] | |||
However, true [[mesothelium]] [[Stain|stains]] positive for [[thrombomodulin]], [[Wilm's tumor|Wilm’s tumor]] 1, [[calretinin]] and negative for [[PAS stain|PAS]]. <ref>{{Cite book|title=Diagnostic histopathology of tumors|last=Fletcher|first=Christopher|publisher=Saunders/Elsevier|year=2013|isbn=9781437715347|location=Philadelphia, PA|pages=}}</ref> | |||
The [[immunohistochemistry staining]] of the cystic tumor of the AV node is in favor of the [[epithelial]] [[differentiation]] of the tumor and supports the labeling of this [[tumor]] as an [[Endoderm|endodermal]] [[Heterotopia (medicine)|heterotopia]]. <ref name="pmid16254122">{{cite journal| author=Evans CA, Suvarna SK| title=Cystic atrioventricular node tumour: not a mesothelioma. | journal=J Clin Pathol | year= 2005 | volume= 58 | issue= 11 | pages= 1232 | pmid=16254122 | doi= | pmc=1770778 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16254122 }} </ref> | |||
==Causes== | ==Causes== | ||
The cause of the cystic tumor of the AV node has not been identified. Other mid-line [[developmental]] defects are seen in 10% of the patients. <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref>It suggests that a [[genetic]] [[defect]] might involve migration of [[embryological]] [[tissues]] and [[cardiac]] [[neural crest cell]] [[development]] <ref name="pmid15716232">{{cite journal| author=Cameselle-Teijeiro J, Abdulkader I, Soares P, Alfonsín-Barreiro N, Moldes-Boullosa J, Sobrinho-Simões M| title=Cystic tumor of the atrioventricular node of the heart appears to be the heart equivalent of the solid cell nests (ultimobranchial rests) of the thyroid. | journal=Am J Clin Pathol | year= 2005 | volume= 123 | issue= 3 | pages= 369-75 | pmid=15716232 | doi=10.1309/GWT2-PY0T-77PB-BA1A | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15716232 }} </ref> <ref name="pmid2222148">{{cite journal| author=Burke AP, Anderson PG, Virmani R, James TN, Herrera GA, Ceballos R| title=Tumor of the atrioventricular nodal region. A clinical and immunohistochemical study. | journal=Arch Pathol Lab Med | year= 1990 | volume= 114 | issue= 10 | pages= 1057-62 | pmid=2222148 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2222148 }} </ref> with possible [[familial]] [[predisposition]]. <ref name="pmid3839372">{{cite journal| author=Travers H| title=Congenital polycystic tumor of the atrioventricular node. | journal=Arch Pathol Lab Med | year= 1985 | volume= 109 | issue= 8 | pages= 704-6 | pmid=3839372 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3839372 }} </ref> Considering the absence of [[Mitosis|mitoses]] in the [[tumor]], it is suggested to be resulted from a [[dilatation]] of [[cystic]] spaces rather than true [[neoplasm]]. <ref name="pmid6647106">{{cite journal| author=Thorgeirsson G, Liebman J| title=Mesothelioma of the AV node. | journal=Pediatr Cardiol | year= 1983 | volume= 4 | issue= 3 | pages= 219-23 | pmid=6647106 | doi=10.1007/BF02242259 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=6647106 }} </ref> <ref name="pmid10724528">{{cite journal| author=Ford SE| title=Congenital cystic tumors of the atrio-ventricular node: successful demonstration by an abbreviated dissection of the conduction system. | journal=Cardiovasc Pathol | year= 1999 | volume= 8 | issue= 4 | pages= 233-7 | pmid=10724528 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10724528 }} </ref> | |||
==Differentiating Cystic Tumor of the | ==Differentiating Cystic Tumor of the AV node from Other Diseases== | ||
Cystic tumor of the AV node must be [[Differentiate|differentiated]] from other [[Cardiac tumors differential diagnosis|cardiac tumors]]. | |||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
[[Primary cardiac neoplasms|Primary cardiac tumors]] are [[rare]] with an [[incidence]] of 0.0017% to 0.03% of all [[Autopsy|autopsies]]. <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> <ref name="pmid26838113">{{cite journal| author=Miller DV| title=Cardiac Tumors. | journal=Surg Pathol Clin | year= 2012 | volume= 5 | issue= 2 | pages= 453-83 | pmid=26838113 | doi=10.1016/j.path.2012.04.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26838113 }} </ref> Cystic tumor of the AV node accounts for 2.7% of [[cardiac]] [[Tumor|tumors]] and it is the most common [[Primary cardiac neoplasms|primary cardiac tumor]] that causes [[sudden death]]. <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> <ref name="pmid5897246">{{cite journal| author=Wolf PL, Bing R| title=The smallest tumor which causes sudden death. | journal=JAMA | year= 1965 | volume= 194 | issue= 6 | pages= 674-5 | pmid=5897246 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5897246 }} </ref> | |||
There is no [[racial]] or [[Ethnic group|ethnic]] [[predilection]] to the cystic tumor of the AV node. | |||
There | |||
Women are more commonly affected by the cystic tumor of the AV node than men. The female to male [[ratio]] is approximately 3 to 1. <ref name="pmid26838113">{{cite journal| author=Miller DV| title=Cardiac Tumors. | journal=Surg Pathol Clin | year= 2012 | volume= 5 | issue= 2 | pages= 453-83 | pmid=26838113 | doi=10.1016/j.path.2012.04.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26838113 }} </ref> | |||
The | The cystic tumor of the AV node is usually diagnosed in the fourth decade of life. <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> | ||
==Risk Factors== | |||
There are no established [[risk factor]]<nowiki/>s for the cystic tumor of the AV node. | |||
==Screening== | ==Screening== | ||
There is insufficient evidence to recommend routine screening for cystic tumor of the | There is insufficient evidence to recommend routine [[screening]] for the cystic tumor of the AV node. | ||
==Natural History, Complications, and Prognosis== | ==Natural History, Complications, and Prognosis== | ||
Cystic tumor of the AV node is most commonly diagnosed [[postmortem]] in individuals died due to [[sudden cardiac death]]. <ref name="pmid20020153">{{cite journal| author=Patel J, Sheppard MN| title=Cystic tumour of the atrioventricular node: three cases of sudden death. | journal=Int J Legal Med | year= 2011 | volume= 125 | issue= 1 | pages= 139-42 | pmid=20020153 | doi=10.1007/s00414-009-0399-7 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20020153 }} <ref name="pmid5897246">{{cite journal |vauthors=Wolf PL, Bing R |title=The smallest tumor which causes sudden death |journal=JAMA |volume=194 |issue=6 |pages=674–5 |date=November 1965 |pmid=5897246 |doi= |url=}}</ref> [[Fatal arrhythmias]] including [[ventricular tachycardia]] or [[ventricular fibrillation]] may occur despite [[pacemaker]] placement. <ref name="pmid21056880">{{cite journal| author=Maujean G, Tabib A, Malicier D, Fanton L| title=Sudden death due to a cystic atrio-ventricular node tumour. | journal=J Forensic Leg Med | year= 2010 | volume= 17 | issue= 8 | pages= 437-8 | pmid=21056880 | doi=10.1016/j.jflm.2010.08.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21056880 }} </ref> <ref name="pmid20020153">{{cite journal| author=Patel J, Sheppard MN| title=Cystic tumour of the atrioventricular node: three cases of sudden death. | journal=Int J Legal Med | year= 2011 | volume= 125 | issue= 1 | pages= 139-42 | pmid=20020153 | doi=10.1007/s00414-009-0399-7 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20020153 }} </ref> | |||
==Diagnosis== | ==Diagnosis== | ||
===Diagnostic Study of Choice=== | ===Diagnostic Study of Choice=== | ||
There are no established [[criteria]] for the [[diagnosis]] of cystic tumor of the AV node. Only a few cases of cystic tumor of the AV node has been [[Diagnose|diagnosed]] antemortem. [[Imaging]] modalities including [[echocardiography]] and [[MRI]] are helpful in making the diagnosis. <ref name="pmid25303965">{{cite journal| author=Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A et al.| title=Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings. | journal=J Thorac Imaging | year= 2014 | volume= 29 | issue= 6 | pages= W97-9 | pmid=25303965 | doi=10.1097/RTI.0000000000000111 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25303965 }} </ref> [[Histopathological]] [[examination]] of the [[Resection|resected]] [[tumor]] provides the definitive [[diagnosis]]. <ref name="pmid25303965">{{cite journal |vauthors=Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A, Hayashi T, Amano A, Kuwatsuru R |title=Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings |journal=J Thorac Imaging |volume=29 |issue=6 |pages=W97–9 |date=November 2014 |pmid=25303965 |doi=10.1097/RTI.0000000000000111 |url=}}</ref> | |||
===History and Symptoms=== | ===History and Symptoms=== | ||
The | The presentation of the cystic tumor of the AV node can range from being [[asymptomatic]] to [[sudden cardiac death]]. <ref name="pmid20020153">{{cite journal| author=Patel J, Sheppard MN| title=Cystic tumour of the atrioventricular node: three cases of sudden death. | journal=Int J Legal Med | year= 2011 | volume= 125 | issue= 1 | pages= 139-42 | pmid=20020153 | doi=10.1007/s00414-009-0399-7 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20020153 }} </ref><ref name="pmid25303965">{{cite journal |vauthors=Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A, Hayashi T, Amano A, Kuwatsuru R |title=Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings |journal=J Thorac Imaging |volume=29 |issue=6 |pages=W97–9 |date=November 2014 |pmid=25303965 |doi=10.1097/RTI.0000000000000111 |url=}}</ref> | ||
Typical [[Symptom|symptoms]] are: <ref name="pmid10722558">{{cite journal| author=Paniagua JR, Sadaba JR, Davidson LA, Munsch CM| title=Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery. | journal=Heart | year= 2000 | volume= 83 | issue= 4 | pages= E6 | pmid=10722558 | doi=10.1136/heart.83.4.e6 | pmc=1729374 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10722558 }} </ref> <ref name="pmid28438795">{{cite journal |vauthors=Abuzeid W, Myers RBH |title=Cystic tumour of the atrioventricular node: treatment dilemma |journal=BMJ Case Rep |volume=2017 |issue= |pages= |date=April 2017 |pmid=28438795 |pmc=5534749 |doi=10.1136/bcr-2017-219314 |url=}}</ref><ref name="pmid21820324">{{cite journal| author=Law KB, Feng T, Nair V, Cusimano RJ, Butany J| title=Cystic tumor of the atrioventricular node: rare antemortem diagnosis. | journal=Cardiovasc Pathol | year= 2012 | volume= 21 | issue= 2 | pages= 120-7 | pmid=21820324 | doi=10.1016/j.carpath.2011.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21820324 }} </ref> <ref name="pmid5016834">{{cite journal| author=Lewman LV, Demany MA, Zimmerman HA| title=Congenital tumor of atrioventricular node with complete heart block and sudden death. Mesothelioma or lymphangio-endothelioma of atrioventricular node. | journal=Am J Cardiol | year= 1972 | volume= 29 | issue= 4 | pages= 554-7 | pmid=5016834 | doi=10.1016/0002-9149(72)90448-1 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5016834 }} </ref> | |||
*[[Palpitations]] | |||
*[[Dyspnea]] | |||
*[[syncope]] | |||
*[[Dizziness]] | |||
Patients may also present with partial or [[complete heart block]]. <ref name="pmid21820324">{{cite journal| author=Law KB, Feng T, Nair V, Cusimano RJ, Butany J| title=Cystic tumor of the atrioventricular node: rare antemortem diagnosis. | journal=Cardiovasc Pathol | year= 2012 | volume= 21 | issue= 2 | pages= 120-7 | pmid=21820324 | doi=10.1016/j.carpath.2011.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21820324 }} </ref> <ref name="pmid5124984">{{cite journal| author=Hopkinson JM, Newcombe CP| title=Heart block due to epithelial heterotopia. | journal=J Pathol | year= 1971 | volume= 104 | issue= 3 | pages= 218-20 | pmid=5124984 | doi=10.1002/path.1711040312 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5124984 }} </ref> <ref name="pmid21056880">{{cite journal| author=Maujean G, Tabib A, Malicier D, Fanton L| title=Sudden death due to a cystic atrio-ventricular node tumour. | journal=J Forensic Leg Med | year= 2010 | volume= 17 | issue= 8 | pages= 437-8 | pmid=21056880 | doi=10.1016/j.jflm.2010.08.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21056880 }} </ref> | |||
===Physical Examination=== | ===Physical Examination=== | ||
[[Physical examination]] of [[Patient|patients]] with cystic tumor of the AV node is usually unremarkable. | |||
===Laboratory Findings=== | ===Laboratory Findings=== | ||
There are no [[Diagnosis|diagnostic]] [[laboratory]] findings associated with cystic tumor of the AV node. | |||
===Electrocardiogram=== | ===Electrocardiogram=== | ||
An [[ECG]] may be helpful in the [[diagnosis]] of cystic tumor of the AV node. [[ECG]] might show partial or [[complete heart block]]. <ref name="pmid21820324">{{cite journal| author=Law KB, Feng T, Nair V, Cusimano RJ, Butany J| title=Cystic tumor of the atrioventricular node: rare antemortem diagnosis. | journal=Cardiovasc Pathol | year= 2012 | volume= 21 | issue= 2 | pages= 120-7 | pmid=21820324 | doi=10.1016/j.carpath.2011.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21820324 }} </ref><ref name="pmid28438795">{{cite journal| author=Abuzeid W, Myers RBH| title=Cystic tumour of the atrioventricular node: treatment dilemma. | journal=BMJ Case Rep | year= 2017 | volume= 2017 | issue= | pages= | pmid=28438795 | doi=10.1136/bcr-2017-219314 | pmc=5534749 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28438795 }} </ref><ref name="pmid24182482">{{cite journal| author=Careddu L, Pantaleo A, Savini C, Di Eusanio M, Leone O, Di Bartolomeo R| title=Cystic atrioventricular node tumor excision by minimally invasive surgery. | journal=Ann Thorac Surg | year= 2013 | volume= 96 | issue= 5 | pages= 1873-5 | pmid=24182482 | doi=10.1016/j.athoracsur.2013.03.036 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24182482 }} </ref> | |||
===X-ray=== | ===X-ray=== | ||
There are no x-ray findings associated with cystic tumor of the | There are no [[x-ray]] findings associated with cystic tumor of the AV node. | ||
===Echocardiography or Ultrasound=== | ===Echocardiography or Ultrasound=== | ||
[[Echocardiography]] may be helpful in the [[diagnosis]] of cystic tumor of the AV node, showing a [[mass]] at the site of the tumor. <ref name="pmid28438795">{{cite journal| author=Abuzeid W, Myers RBH| title=Cystic tumour of the atrioventricular node: treatment dilemma. | journal=BMJ Case Rep | year= 2017 | volume= 2017 | issue= | pages= | pmid=28438795 | doi=10.1136/bcr-2017-219314 | pmc=5534749 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28438795 }} </ref> <ref name="pmid21820324">{{cite journal| author=Law KB, Feng T, Nair V, Cusimano RJ, Butany J| title=Cystic tumor of the atrioventricular node: rare antemortem diagnosis. | journal=Cardiovasc Pathol | year= 2012 | volume= 21 | issue= 2 | pages= 120-7 | pmid=21820324 | doi=10.1016/j.carpath.2011.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21820324 }} </ref> <ref name="pmid24182482">{{cite journal| author=Careddu L, Pantaleo A, Savini C, Di Eusanio M, Leone O, Di Bartolomeo R| title=Cystic atrioventricular node tumor excision by minimally invasive surgery. | journal=Ann Thorac Surg | year= 2013 | volume= 96 | issue= 5 | pages= 1873-5 | pmid=24182482 | doi=10.1016/j.athoracsur.2013.03.036 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24182482 }} </ref> | |||
===CT scan=== | ===CT scan=== | ||
Only a few cases of cystic tumor of the AV node have been reported antemortem. Therefore, the data regarding the [[imaging]] findings are limited. Reports have shown either a high-[[attenuation]] <ref name="pmid16195634">{{cite journal| author=Saito S, Kobayashi J, Tagusari O, Bando K, Niwaya K, Nakajima H et al.| title=Successful excision of a cystic tumor of the atrioventricular nodal region. | journal=Circ J | year= 2005 | volume= 69 | issue= 10 | pages= 1293-4 | pmid=16195634 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16195634 }} </ref> or low-attenuation [[Lesion|lesions]] on [[Computed tomography|CT]] [[images]]. <ref name="Kaminishi">{{cite journal| author= Kaminishi Y, Watanabe Y, Nakata H, et al. | title= Cystic tumor of the atrioventricular nodal region. | journal= . Jpn J Thorac Cardiovasc Surg. | year= 2002 | volume= 50 | issue= | pages= 37-39 | }} </ref> | |||
===MRI=== | ===MRI=== | ||
[[Cardiac MRI]] may be helpful in the [[diagnosis]] of the cystic tumor of the AV node. High-signal [[intensity]] lesion on T1-weighted <ref name="pmid10722558">{{cite journal| author=Paniagua JR, Sadaba JR, Davidson LA, Munsch CM| title=Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery. | journal=Heart | year= 2000 | volume= 83 | issue= 4 | pages= E6 | pmid=10722558 | doi=10.1136/heart.83.4.e6 | pmc=1729374 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10722558 }} </ref> <ref name="pmid16195634">{{cite journal| author=Saito S, Kobayashi J, Tagusari O, Bando K, Niwaya K, Nakajima H et al.| title=Successful excision of a cystic tumor of the atrioventricular nodal region. | journal=Circ J | year= 2005 | volume= 69 | issue= 10 | pages= 1293-4 | pmid=16195634 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16195634 }} </ref> <ref name="pmid25303965">{{cite journal| author=Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A et al.| title=Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings. | journal=J Thorac Imaging | year= 2014 | volume= 29 | issue= 6 | pages= W97-9 | pmid=25303965 | doi=10.1097/RTI.0000000000000111 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25303965 }} </ref>and T2-weighted [[MRI]] <ref name="pmid16195634">{{cite journal| author=Saito S, Kobayashi J, Tagusari O, Bando K, Niwaya K, Nakajima H et al.| title=Successful excision of a cystic tumor of the atrioventricular nodal region. | journal=Circ J | year= 2005 | volume= 69 | issue= 10 | pages= 1293-4 | pmid=16195634 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16195634 }} </ref> or low signal intensity on T2-weighted MRI <ref name="pmid25303965">{{cite journal| author=Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A et al.| title=Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings. | journal=J Thorac Imaging | year= 2014 | volume= 29 | issue= 6 | pages= W97-9 | pmid=25303965 | doi=10.1097/RTI.0000000000000111 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25303965 }} </ref> have been reported. | |||
===Other Imaging Findings=== | ===Other Imaging Findings=== | ||
There are no other imaging findings associated with cystic tumor of the | There are no other [[imaging]] findings associated with cystic tumor of the AV node. | ||
===Other Diagnostic Studies=== | ===Other Diagnostic Studies=== | ||
There are no other diagnostic studies associated with cystic tumor of the | There are no other [[diagnostic]] studies associated with cystic tumor of the AV node. | ||
==Treatment== | ==Treatment== | ||
===Medical Therapy=== | ===Medical Therapy=== | ||
There is no [[medical]] treatment for the cystic tumor of the AV node. | |||
===Surgery=== | ===Surgery=== | ||
Because of the critical location of the tumor and its unfavorable prognosis, surgical excision is the mainstay of treatment for cystic tumor of the | Because of the critical location of the [[tumor]] and its unfavorable [[prognosis]], [[Surgery|surgical]] [[excision]] is the mainstay of treatment for cystic tumor of the AV node. [[Anti-arrhythmic medications|Anti-arrhythmic drugs]] and lifelong [[pacemaker]] placement may be necessary after [[excision]] to manage any post-surgical [[AV block]]. <ref name="pmid26838113">{{cite journal| author=Miller DV| title=Cardiac Tumors. | journal=Surg Pathol Clin | year= 2012 | volume= 5 | issue= 2 | pages= 453-83 | pmid=26838113 | doi=10.1016/j.path.2012.04.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26838113 }} </ref> <ref name="pmid26725181">{{cite journal| author=Burke A, Tavora F| title=The 2015 WHO Classification of Tumors of the Heart and Pericardium. | journal=J Thorac Oncol | year= 2016 | volume= 11 | issue= 4 | pages= 441-52 | pmid=26725181 | doi=10.1016/j.jtho.2015.11.009 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26725181 }} </ref> | ||
===Primary Prevention=== | ===Primary Prevention=== | ||
There are no established measures for the primary prevention of cystic tumor of the | There are no established measures for the [[primary prevention]] of the cystic tumor of the AV node. | ||
===Secondary Prevention=== | ===Secondary Prevention=== | ||
There are no established measures for the secondary prevention of cystic tumor of the | There are no established measures for the [[secondary prevention]] of the cystic tumor of the AV node. | ||
==References== | ==References== |
Latest revision as of 20:47, 12 September 2019
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mandana Chitsazan, M.D. [2]
Synonyms and keywords:Mesothelioma of the AV node, AV node tumor
Overview
Cystic tumor of the atrioventricular (AV) node is a rare benign congenital tumor. The origin of the cystic tumor of the AV node is still controversial. Although it is called mesothelioma of the AV node, it appears to have endodermal origin. The size of the tumor ranges from 0.5 mm to 30 mm and size of the tumor is not correlated with the occurrence of fatal arrhythmias. On gross pathology, small multiocular cysts are characteristic findings of the cystic tumor of the AV node. On microscopic examination, solid cell nests and cystic structures lined by flattended cuboidal and squamous epithelium mixed with rare neuroendocrine cells (C cells) are characteristic findings of the cystic tumor of the AV node. The immunohistochemical staining of the cystic tumor of the AV node is in favor of the epithelial differentiation of the tumor. Cystic tumor of the AV node is most commonly diagnosed postmortem in individuals died due to sudden cardiac death. Fatal arrhythmias including ventricular tachycardia or ventricular fibrillation may occur despite pacemaker placement. Only a few cases of cystic tumor of the AV node has been diagnosed antemortem. Imaging modalities including echocardiography and MRI are helpful in making the diagnosis. Histopathological examination of the resected tumor provides the definitive diagnosis. Because of the critical location of the tumor and its unfavorable prognosis, surgical excision is the mainstay of treatment for cystic tumor of the AV node. Anti-arrhythmic drugs and lifelong pacemaker placement may be necessary after excision to manage any post-surgical AV block.
Historical Perspective
Cystic tumor of the atrioventricular (AV) node was first reported by Armstrong and Mönckeberg in 1911. [1]
Classification
There is no established system for the staging of the cystic tumor of the AV node.
Pathophysiology
The cystic tumor of the AV node is a benign congenital tumor. Although it is also called mesothelioma of the AV node, it appears to be a misnomer. The origin of the cystic tumor of the AV node is still controversial. It is believed that it has endodermal origin, derived from congenital rests during embryogenesis. [2] [3] One study suggested that cystic tumor of the AV node and solid cell nests of the thyroid have similar structures and may share the same developmental process; therefore it is assumed that cystic tumor of the AV node is an ultimobranchial heterotopia. [4]
On gross pathology, small multiocular cysts are characteristic findings of the cystic tumor of the AV node. The tumor may be invisible from the endocardial surface of the heart. Therefore, sectioning through the infero-medial tricuspid annulus might be required. [5] [6] The size of the tumor ranges from 0.5 mm to 30 mm and the size of the tumor is not correlated with the occurrence of fatal arrhythmias. [7]
On microscopic histopathological analysis, solid cell nests and cystic structures lined by flattened cuboidal or squamous epithelium mixed with rare neuroendocrine cells (C cells) are characteristic findings of the cystic tumor of the AV node. [5] [6] [8]
On immunohistochemical staining, the main tumor cells stain positive for: [9]
- Cytokeratin CAM5.2
- Cytokeratin AE1/AE3
- Cytokeratin 34βE12
- Cytokeratin 5/6 (CK5/6)
- Cytokeratin 7 (CK7)
- Epithelial membrane antigen (EMA)
- Carcinoembryonic antigen (CEA)
- Carbohydrate antigen (CA)19.9
- p63
- bcl2
- Galectin-3
The neuroendocrine cells of the lesion stain positive for: [10] [8] [9]
- CAM5.2
- Pan-keratin (AE1/AE3)
- CEA
- Calcitonin
- Chromogranin
- Synaptophysin
- hyroid Transcription Factor 1 (TTF1)
The tumor stains negative for: [10] [8] [9]
- Keratin 20 (CK20)
- p53
- Bcl-2
- Cyclin D1
- Cytokeratin 20 (CK20)
- Vimentin
- CD31
- Factor VIII related antigen
- Estrogen receptor
- Progesterone receptor
- Thrombomodulin
- Wilm’s tumor 1
- Calretinin
However, true mesothelium stains positive for thrombomodulin, Wilm’s tumor 1, calretinin and negative for PAS. [11]
The immunohistochemistry staining of the cystic tumor of the AV node is in favor of the epithelial differentiation of the tumor and supports the labeling of this tumor as an endodermal heterotopia. [10]
Causes
The cause of the cystic tumor of the AV node has not been identified. Other mid-line developmental defects are seen in 10% of the patients. [6]It suggests that a genetic defect might involve migration of embryological tissues and cardiac neural crest cell development [4] [2] with possible familial predisposition. [12] Considering the absence of mitoses in the tumor, it is suggested to be resulted from a dilatation of cystic spaces rather than true neoplasm. [13] [14]
Differentiating Cystic Tumor of the AV node from Other Diseases
Cystic tumor of the AV node must be differentiated from other cardiac tumors.
Epidemiology and Demographics
Primary cardiac tumors are rare with an incidence of 0.0017% to 0.03% of all autopsies. [6] [5] Cystic tumor of the AV node accounts for 2.7% of cardiac tumors and it is the most common primary cardiac tumor that causes sudden death. [6] [15]
There is no racial or ethnic predilection to the cystic tumor of the AV node.
Women are more commonly affected by the cystic tumor of the AV node than men. The female to male ratio is approximately 3 to 1. [5]
The cystic tumor of the AV node is usually diagnosed in the fourth decade of life. [6]
Risk Factors
There are no established risk factors for the cystic tumor of the AV node.
Screening
There is insufficient evidence to recommend routine screening for the cystic tumor of the AV node.
Natural History, Complications, and Prognosis
Cystic tumor of the AV node is most commonly diagnosed postmortem in individuals died due to sudden cardiac death. Fatal arrhythmias including ventricular tachycardia or ventricular fibrillation may occur despite pacemaker placement. [16] [17]
Diagnosis
Diagnostic Study of Choice
There are no established criteria for the diagnosis of cystic tumor of the AV node. Only a few cases of cystic tumor of the AV node has been diagnosed antemortem. Imaging modalities including echocardiography and MRI are helpful in making the diagnosis. [18] Histopathological examination of the resected tumor provides the definitive diagnosis. [18]
History and Symptoms
The presentation of the cystic tumor of the AV node can range from being asymptomatic to sudden cardiac death. [17][18] Typical symptoms are: [8] [19][20] [21]
Patients may also present with partial or complete heart block. [20] [22] [16]
Physical Examination
Physical examination of patients with cystic tumor of the AV node is usually unremarkable.
Laboratory Findings
There are no diagnostic laboratory findings associated with cystic tumor of the AV node.
Electrocardiogram
An ECG may be helpful in the diagnosis of cystic tumor of the AV node. ECG might show partial or complete heart block. [20][19][23]
X-ray
There are no x-ray findings associated with cystic tumor of the AV node.
Echocardiography or Ultrasound
Echocardiography may be helpful in the diagnosis of cystic tumor of the AV node, showing a mass at the site of the tumor. [19] [20] [23]
CT scan
Only a few cases of cystic tumor of the AV node have been reported antemortem. Therefore, the data regarding the imaging findings are limited. Reports have shown either a high-attenuation [24] or low-attenuation lesions on CT images. [25]
MRI
Cardiac MRI may be helpful in the diagnosis of the cystic tumor of the AV node. High-signal intensity lesion on T1-weighted [8] [24] [18]and T2-weighted MRI [24] or low signal intensity on T2-weighted MRI [18] have been reported.
Other Imaging Findings
There are no other imaging findings associated with cystic tumor of the AV node.
Other Diagnostic Studies
There are no other diagnostic studies associated with cystic tumor of the AV node.
Treatment
Medical Therapy
There is no medical treatment for the cystic tumor of the AV node.
Surgery
Because of the critical location of the tumor and its unfavorable prognosis, surgical excision is the mainstay of treatment for cystic tumor of the AV node. Anti-arrhythmic drugs and lifelong pacemaker placement may be necessary after excision to manage any post-surgical AV block. [5] [6]
Primary Prevention
There are no established measures for the primary prevention of the cystic tumor of the AV node.
Secondary Prevention
There are no established measures for the secondary prevention of the cystic tumor of the AV node.
References
- ↑ Armstrong H, Mönckeberg JG (1911). "Herzblock, bedingt durch primären Herztumor, bei einem 5 jährigen Kinde". Dtsch Arch Klin Med. 102: 144–146.
- ↑ 2.0 2.1 Burke AP, Anderson PG, Virmani R, James TN, Herrera GA, Ceballos R (1990). "Tumor of the atrioventricular nodal region. A clinical and immunohistochemical study". Arch Pathol Lab Med. 114 (10): 1057–62. PMID 2222148.
- ↑ Cameselle-Teijeiro J, Santías RR, Nallib IA, Forteza J, Barreiro NA (2010). "Cystic tumor of the atrioventricular node: a rare cardiac pseudoneoplastic lesion". Arch Pathol Lab Med. 134 (11): 1584–6. doi:10.1043/2010-0268-LER.1. PMID 21043810.
- ↑ 4.0 4.1 Cameselle-Teijeiro J, Abdulkader I, Soares P, Alfonsín-Barreiro N, Moldes-Boullosa J, Sobrinho-Simões M (2005). "Cystic tumor of the atrioventricular node of the heart appears to be the heart equivalent of the solid cell nests (ultimobranchial rests) of the thyroid". Am J Clin Pathol. 123 (3): 369–75. doi:10.1309/GWT2-PY0T-77PB-BA1A. PMID 15716232.
- ↑ 5.0 5.1 5.2 5.3 5.4 Miller DV (2012). "Cardiac Tumors". Surg Pathol Clin. 5 (2): 453–83. doi:10.1016/j.path.2012.04.007. PMID 26838113.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Burke A, Tavora F (2016). "The 2015 WHO Classification of Tumors of the Heart and Pericardium". J Thorac Oncol. 11 (4): 441–52. doi:10.1016/j.jtho.2015.11.009. PMID 26725181.
- ↑ Guo J, Zuo S, Lin C, Ji Y (May 2009). "Surgical treatment of a giant cystic tumor of the atrioventricular nodal region". Interact Cardiovasc Thorac Surg. 8 (5): 592–3. doi:10.1510/icvts.2008.191866. PMID 19237400.
- ↑ 8.0 8.1 8.2 8.3 8.4 Paniagua JR, Sadaba JR, Davidson LA, Munsch CM (2000). "Cystic tumour of the atrioventricular nodal region: report of a case successfully treated with surgery". Heart. 83 (4): E6. doi:10.1136/heart.83.4.e6. PMC 1729374. PMID 10722558.
- ↑ 9.0 9.1 9.2 Arai T, Kurashima C, Wada S, Chida K, Ohkawa S (1998). "Histological evidence for cell proliferation activity in cystic tumor (endodermal heterotopia) of the atrioventricular node". Pathol Int. 48 (11): 917–23. PMID 9832064.
- ↑ 10.0 10.1 10.2 Evans CA, Suvarna SK (2005). "Cystic atrioventricular node tumour: not a mesothelioma". J Clin Pathol. 58 (11): 1232. PMC 1770778. PMID 16254122.
- ↑ Fletcher, Christopher (2013). Diagnostic histopathology of tumors. Philadelphia, PA: Saunders/Elsevier. ISBN 9781437715347.
- ↑ Travers H (1985). "Congenital polycystic tumor of the atrioventricular node". Arch Pathol Lab Med. 109 (8): 704–6. PMID 3839372.
- ↑ Thorgeirsson G, Liebman J (1983). "Mesothelioma of the AV node". Pediatr Cardiol. 4 (3): 219–23. doi:10.1007/BF02242259. PMID 6647106.
- ↑ Ford SE (1999). "Congenital cystic tumors of the atrio-ventricular node: successful demonstration by an abbreviated dissection of the conduction system". Cardiovasc Pathol. 8 (4): 233–7. PMID 10724528.
- ↑ Wolf PL, Bing R (1965). "The smallest tumor which causes sudden death". JAMA. 194 (6): 674–5. PMID 5897246.
- ↑ 16.0 16.1 Maujean G, Tabib A, Malicier D, Fanton L (2010). "Sudden death due to a cystic atrio-ventricular node tumour". J Forensic Leg Med. 17 (8): 437–8. doi:10.1016/j.jflm.2010.08.009. PMID 21056880.
- ↑ 17.0 17.1 Patel J, Sheppard MN (2011). "Cystic tumour of the atrioventricular node: three cases of sudden death". Int J Legal Med. 125 (1): 139–42. doi:10.1007/s00414-009-0399-7. PMID 20020153.
- ↑ 18.0 18.1 18.2 18.3 18.4 Suzuki K, Matsushita S, Suzuki H, Kuroda K, Inaba H, Arakawa A; et al. (2014). "Cystic tumor of the atrioventricular node: computed tomography and magnetic resonance imaging findings". J Thorac Imaging. 29 (6): W97–9. doi:10.1097/RTI.0000000000000111. PMID 25303965.
- ↑ 19.0 19.1 19.2 Abuzeid W, Myers R (April 2017). "Cystic tumour of the atrioventricular node: treatment dilemma". BMJ Case Rep. 2017. doi:10.1136/bcr-2017-219314. PMC 5534749. PMID 28438795. Vancouver style error: initials (help)
- ↑ 20.0 20.1 20.2 20.3 Law KB, Feng T, Nair V, Cusimano RJ, Butany J (2012). "Cystic tumor of the atrioventricular node: rare antemortem diagnosis". Cardiovasc Pathol. 21 (2): 120–7. doi:10.1016/j.carpath.2011.05.004. PMID 21820324.
- ↑ Lewman LV, Demany MA, Zimmerman HA (1972). "Congenital tumor of atrioventricular node with complete heart block and sudden death. Mesothelioma or lymphangio-endothelioma of atrioventricular node". Am J Cardiol. 29 (4): 554–7. doi:10.1016/0002-9149(72)90448-1. PMID 5016834.
- ↑ Hopkinson JM, Newcombe CP (1971). "Heart block due to epithelial heterotopia". J Pathol. 104 (3): 218–20. doi:10.1002/path.1711040312. PMID 5124984.
- ↑ 23.0 23.1 Careddu L, Pantaleo A, Savini C, Di Eusanio M, Leone O, Di Bartolomeo R (2013). "Cystic atrioventricular node tumor excision by minimally invasive surgery". Ann Thorac Surg. 96 (5): 1873–5. doi:10.1016/j.athoracsur.2013.03.036. PMID 24182482.
- ↑ 24.0 24.1 24.2 Saito S, Kobayashi J, Tagusari O, Bando K, Niwaya K, Nakajima H; et al. (2005). "Successful excision of a cystic tumor of the atrioventricular nodal region". Circ J. 69 (10): 1293–4. PMID 16195634.
- ↑ Kaminishi Y, Watanabe Y, Nakata H; et al. (2002). "Cystic tumor of the atrioventricular nodal region". . Jpn J Thorac Cardiovasc Surg. 50: 37–39.