Cystic Tumor of the Atrioventricular Node
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mandana Chitsazan, M.D. [2]
Synonyms and keywords:
Overview
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 ultimobrachial 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)
- Eithelial 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 midline 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
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. [16][17] Fatal arrhythmias including ventricular tachycardia or ventricular fibrillation may occur despite pacemaker placement. [18] [16]
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 cyctic tumor of the AV node has been diagnosed antemortem. Imaging modalities including echocardiography and MRI were helpful in making the diagnosis. [19] Histopahtologic examination of the resected tumor provides the definitive diagnosis. [20]
History and Symptoms
The presentation of the cystic tumor of the AV node can range from being asymptomatic to sudden cardiac death. [16][20]Typical symptoms are: [8] [21] [22] [23]
- Palpitations
- Dyspnea
- syncope
- Dizziness
Patients may also present with partial or complete heart block. [22] [24] [18]
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. [22][25][26]
X-ray
There are no x-ray findings associated with cystic tumor of the AV node.
Echocardiography or Ultrasound
Echocardiography/ultrasound may be helpful in the diagnosis of cystic tumor of the AV node, showing a mass at the site of the tumor. [25] [22] [26]
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 [27] or low-attenuation lesions on CT images. [28]
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] [27] [19]and T2-weighted MRI [27] or low signal intensity on T2-weighted MRI [19] 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 atrioventricular 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.
- ↑ Schmoldt A, Benthe HF, Haberland G (1975). "Digitoxin metabolism by rat liver microsomes". Biochem Pharmacol. 24 (17): 1639–41. PMID https://doi.org/10.1510/icvts.2008.191866 Check
|pmid=value (help). - ↑ 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 16.2 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.
- ↑ Schmoldt A, Benthe HF, Haberland G (1975). "Digitoxin metabolism by rat liver microsomes". Biochem Pharmacol. 24 (17): 1639–41. PMID doi:10.1001/jama.1965.03090190096030 Check
|pmid=value (help). - ↑ 18.0 18.1 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.
- ↑ 19.0 19.1 19.2 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.
- ↑ 20.0 20.1 Schmoldt A, Benthe HF, Haberland G (1975). "Digitoxin metabolism by rat liver microsomes". Biochem Pharmacol. 24 (17): 1639–41. PMID doi:10.1097/rti.0000000000000111 Check
|pmid=value (help). - ↑ Schmoldt A, Benthe HF, Haberland G (1975). "Digitoxin metabolism by rat liver microsomes". Biochem Pharmacol. 24 (17): 1639–41. PMID http://dx.doi.org/10.1136/bcr-2017-219314 Check
|pmid=value (help). - ↑ 22.0 22.1 22.2 22.3 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.
- ↑ 25.0 25.1 Abuzeid W, Myers RBH (2017). "Cystic tumour of the atrioventricular node: treatment dilemma". BMJ Case Rep. 2017. doi:10.1136/bcr-2017-219314. PMC 5534749. PMID 28438795.
- ↑ 26.0 26.1 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.
- ↑ 27.0 27.1 27.2 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.