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]
On microscopic histopathological analysis, solid cell nests and cystic structures lined by flattened cuboidal or squamous epithelium mixed with rare neuroendocrine cells are characteristic findings of the cystic tumor of the AV node. [5] [6]
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. [7] Considering the absence of mitoses in the tumor, it is suggested to be resulted from a dilatation of cystic spaces rather than true neoplasm. [8] [9]
Differentiating ((Page name)) from Other Diseases
[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as [differential dx1], [differential dx2], and [differential dx3].
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[Disease name] must be differentiated from [[differential dx1], [differential dx2], and [differential dx3].
Epidemiology and Demographics
The incidence/prevalence of [disease name] is approximately [number range] per 100,000 individuals worldwide.
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.Miller
The cystic tumor of the AV node is usually diagnosed in the fourth decade of life. WHO
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
If left untreated, [#]% of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
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Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
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Prognosis is generally excellent/good/poor, and the 1/5/10-year mortality/survival rate of patients with [disease name] is approximately [#]%.
Diagnosis
Diagnostic Study of Choice
The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].
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The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].
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The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].
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There are no established criteria for the diagnosis of [disease name].
History and Symptoms
The majority of patients with [disease name] are asymptomatic.
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The hallmark of [disease name] is [finding]. A positive history of [finding 1] and [finding 2] is suggestive of [disease name]. The most common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3]. Common symptoms of [disease] include [symptom 1], [symptom 2], and [symptom 3]. Less common symptoms of [disease name] include [symptom 1], [symptom 2], and [symptom 3].
Physical Examination
Patients with [disease name] usually appear [general appearance]. Physical examination of patients with [disease name] is usually remarkable for [finding 1], [finding 2], and [finding 3].
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Common physical examination findings of [disease name] include [finding 1], [finding 2], and [finding 3].
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The presence of [finding(s)] on physical examination is diagnostic of [disease name].
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The presence of [finding(s)] on physical examination is highly suggestive of [disease name].
Laboratory Findings
An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
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Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
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[Test] is usually normal among patients with [disease name].
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Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
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There are no diagnostic laboratory findings associated with [disease name].
Electrocardiogram
There are no ECG findings associated with [disease name].
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An ECG may be helpful in the diagnosis of [disease name]. Findings on an ECG suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
X-ray
There are no x-ray findings associated with [disease name].
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An x-ray may be helpful in the diagnosis of [disease name]. Findings on an x-ray suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
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There are no x-ray findings associated with [disease name]. However, an x-ray may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
Echocardiography or Ultrasound
There are no echocardiography/ultrasound findings associated with [disease name].
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Echocardiography/ultrasound may be helpful in the diagnosis of [disease name]. Findings on an echocardiography/ultrasound suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
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There are no echocardiography/ultrasound findings associated with [disease name]. However, an echocardiography/ultrasound may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
CT scan
There are no CT scan findings associated with [disease name].
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[Location] CT scan may be helpful in the diagnosis of [disease name]. Findings on CT scan suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
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There are no CT scan findings associated with [disease name]. However, a CT scan may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
MRI
There are no MRI findings associated with [disease name].
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[Location] MRI may be helpful in the diagnosis of [disease name]. Findings on MRI suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
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There are no MRI findings associated with [disease name]. However, a MRI may be helpful in the diagnosis of complications of [disease name], which include [complication 1], [complication 2], and [complication 3].
Other Imaging Findings
There are no other imaging findings associated with [disease name].
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[Imaging modality] may be helpful in the diagnosis of [disease name]. Findings on an [imaging modality] suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
Other Diagnostic Studies
There are no other diagnostic studies associated with [disease name].
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[Diagnostic study] may be helpful in the diagnosis of [disease name]. Findings suggestive of/diagnostic of [disease name] include [finding 1], [finding 2], and [finding 3].
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Other diagnostic studies for [disease name] include [diagnostic study 1], which demonstrates [finding 1], [finding 2], and [finding 3], and [diagnostic study 2], which demonstrates [finding 1], [finding 2], and [finding 3].
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 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 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.
- ↑ 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.