Ross
413 lines
26 KiB
Markdown
413 lines
26 KiB
Markdown
---
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title: "Rhabdomyoma"
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docid: "2915b0ba-a2fc-425c-beb7-2566dd945aed"
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authors:
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- key: "7e393d6e-f8be-4315-b1cd-b4639ee57a5f"
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value: "Randy R. Richardson, MD"
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- key: "db1ca0c5-292f-4acd-847d-c73a4f4ba734"
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value: "Ryan A. Moore, MD"
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- key: "961f3a7f-ad62-43bc-98f4-5116b17ab812"
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value: "Paula J. Woodward, MD, FSRU"
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breadcrumbs:
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-
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name: "Pediatrics"
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slug: "pediatrics"
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treeNodeId: "a915965c-d436-44cf-ae65-2f22e7246ea4"
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-
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name: "Diagnosis"
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slug: "diagnosis"
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treeNodeId: "2b5cea64-a083-489e-ac0c-ec14ba059026"
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-
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name: "Cardiac"
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slug: "cardiac"
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treeNodeId: "7b8bc469-b6b8-4b0c-a552-38a906099111"
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-
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name: "Miscellaneous"
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slug: "miscellaneous"
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treeNodeId: "f9f94c98-8eb2-46eb-8552-909d84cb1df3"
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-
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name: "Rhabdomyoma"
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slug: "rhabdomyoma"
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treeNodeId: null
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category: "Pediatrics"
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cmeTopicId: "702657a1-8298-4d26-8b2b-5c7249ecda7f"
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documentVersionId: "97f69fa2-7987-4883-9f4f-4275e92bab38"
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imageCount: 18
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lastUpdated: "10/28/21"
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pageDescription: "Rhabdomyoma"
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pageKeywords: "Pediatrics, Diagnosis, Cardiac, Miscellaneous, Rhabdomyoma"
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pageTitle: "Rhabdomyoma | STATdx"
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enhancedTitle: "Rhabdomyoma"
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type: "DX"
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references: true
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breadcrumbs:
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- "Pediatrics"
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- "Diagnosis"
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- "Cardiac"
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- "Miscellaneous"
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- "Rhabdomyoma"
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---
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# KEY FACTS
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- ## Terminology
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- Congenital cardiac hamartoma composed of abnormal myocytes
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- ## Imaging
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- Initial diagnosis is often by fetal &/or postnatal echocardiogram
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- Homogeneous, hyperechoic mass(es) of myocardium
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- Intramyocardial: May appear as wall thickening
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- Intracavitary: Mass attached to myocardium protrudes into lumen
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- MR is leading diagnostic test to delineate location, extent, & tissue characteristics of cardiac masses in children
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- T1: Iso- or mildly hyperintense to myocardium
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- T2: Hyperintense to myocardium
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- 1st-pass perfusion: Hypointense to myocardium
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- Late gadolinium enhancement: Isointense to myocardium
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- Homogeneous appearance on all sequences
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- Normal chest radiograph in small masses
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- Cardiomegaly & signs of congestive heart failure in large masses
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- Image brain (MR) & kidneys (US) for findings of tuberous sclerosis complex (TSC)
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- ~ 100% of patients with multiple rhabdomyomas & 50% with single rhabdomyoma have TSC
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- ## Top Differential Diagnoses
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- Fibroma; pericardial teratoma
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- ## Clinical Issues
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- Cardiac tumors are rare in children
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- Rhabdomyoma is most common pediatric cardiac tumor
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- 75% are diagnosed before 1 year of age
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- Natural history: Up to 93% show spontaneous regression; 70% regress by 4 years of age
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- Surgical excision for minority of cases with refractory arrhythmias or hemodynamic compromise
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# TERMINOLOGY
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- ## Definitions
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- Congenital cardiac hamartoma composed of abnormal myocytes
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# IMAGING
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- ## General Features
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- ### Best diagnostic clue
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- Cardiac mass within or contiguous with myocardium
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- ### Location
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- Interventricular septum > left or right ventricular free wall > > atrium
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- Multiple in up to 90% of cases
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- ### Size
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- < 1 mm to 10 cm; most are 3-4 cm
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- ### Morphology
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- Well-circumscribed, nonencapsulated mass(es)
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- Intramural or exophytic
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- May involve entire wall & appear as wall thickening
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- ## Radiographic Findings
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- Normal chest radiograph in small masses
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- Cardiomegaly & signs of heart failure in large masses
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- ## Echocardiographic Findings
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- Often superior to MR for detection of small masses
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- Homogeneous, hyperechoic mass involving myocardium
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- No blood flow within mass
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- Most often in interventricular septum but can be anywhere
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- May appear as simple wall thickening
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- Intraluminal portion of mass may move across adjacent valve during cardiac cycle
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- ## CT Findings
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- ### NECT
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- Often hypodense compared with myocardium
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- ### CECT
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- Intraluminal component may be assessed with contrast-enhanced studies
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- ## MR Findings
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- ### T1WI
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- Iso- or mildly hyperintense to myocardium
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- ### T2WI
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- Hyperintense to myocardium
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- No change with fat saturation (rules out lipoma)
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- ### T1WI C+
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- Minimal initial enhancement (1st-pass perfusion)
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- Isointense to myocardium with late gadolinium enhancement (LGE)
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- ### SSFP cine
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- Help to differentiate tumor from contractile myocardium, evaluate hemodynamic effect of mass, & look for valvular leak
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- ## Imaging Recommendations
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- ### Best imaging tool
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- Dedicated transthoracic echo in all cases
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- MR is helpful for diagnostic uncertainty, large masses, & surgical planning
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- ### Protocol advice
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- If cardiac mass is identified
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- Look for additional masses
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- Assess location & quality of mass
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- Look for rhythm abnormalities
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- Premature atrial or ventricular contractions are common
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- Supraventricular tachycardia
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- Sinus bradycardia
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- Look for signs of obstruction
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- Ventricular inflow or outflow obstruction
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- May manifest as valve regurgitation or stenosis
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- ↑ cardiac work to overcome obstruction → wall hypertrophy
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- Evaluate for other findings of tuberous sclerosis complex (TSC)
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- In fetus, monitor for signs of hydrops (poor function, effusions)
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# DIFFERENTIAL DIAGNOSIS
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- [Fibroma](/document/fibroma/8ed96e48-c833-4244-87b3-6c34b6ee34f1)
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- Benign congenital cardiac neoplasm composed of fibroblasts & collagen
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- 2nd most common cardiac neoplasm in pediatric population after rhabdomyoma
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- Often arises from interventricular septum or left ventricular free wall
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- MR: Isointense on T1, hypointense on T2
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- [Teratoma](/document/pericardial-teratoma/c115823c-1a05-4185-9ce4-774cd0984249)
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- Pericardial (not myocardial) tumor
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- Exophytic growth (will not be in cardiac chamber)
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- Pericardial effusion is often present
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- Contains all 3 germ cell layers → may be very heterogeneous on imaging with cystic, fatty, & calcified components
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- [Lipoma](/document/cardiac-lipoma/c332f74f-e3cd-47ba-9ff5-5bce83e0e595)
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- Most arise from endocardial surface & protrude into chamber lumen
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- Fat density/intensity on imaging studies allows for specific diagnosis
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- [Myxoma](/document/atrial-myxoma/f9b6c595-ff7b-4731-a799-666983e7f4ed)
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- Majority manifest in adulthood (4th-7th decades)
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- 90% are solitary & atrial in location
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- 75% in left atrium, 10-20% in right atrium
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- Predilection for interatrial septum adjacent to fossa ovalis
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- [Papillary Fibroelastoma](/document/papillary-fibroelastoma/7081571d-9b34-4b8e-9bfa-d08e375a1919)
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- > 90% involve valves
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- Typically small (< 15 mm)
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- [Cardiac Malignancies](/document/cardiac-sarcomas/62ce81d0-f7c9-4a17-9ccf-6204aff4f62e)
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- Extremely uncommon in children
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- Sarcomas account for most (with angiosarcoma being most common)
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- Usually large masses with invasive features
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- Pericardial & pleural effusion are often present
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# PATHOLOGY
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- ## General Features
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- ### Etiology
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- Unknown, but data suggests maternal hormones may play role in growth & development of fetal rhabdomyomas
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- Helps explain regression after delivery
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- ### Genetics
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- Nearly 100% of patients with multiple & 50% with single rhabdomyomas have TSC
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- TSC: Autosomal dominant with variable expressivity
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- ~ 30% of cases are inherited
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- Other cases are due to new mutation
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- Caused by mutations in *TSC1* or*TSC2* genes
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- *TSC1* is located on chromosome 9q
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- Encodes for hamartin protein
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- Complexes with tuberin to regulate cell cycle
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- *TSC2* located on chromosome 16p
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- Encodes for tuberin protein
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- Participates in normal brain development & cardiomyocyte differentiation
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- ### Associated abnormalities
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- Other findings of TSC
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- Brain: Subependymal nodules, cortical/subcortical tubers, subependymal giant cell astrocytoma
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- Lung: Lymphangioleiomyomatosis
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- Kidney: Angiomyolipomas & cysts
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- Eye: Retinal hamartomas
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- Nails: Ungual fibromas
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- Pathophysiology
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- Mass may interfere with myocardial contraction
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- Exophytic masses frequently obstruct blood flow or cause valvular insufficiency
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- ## Gross Pathologic & Surgical Features
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- Well-circumscribed, intramyocardial or exophytic mass(es)
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- ## Microscopic Features
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- Large, vacuolated myocytes
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- Glycogen-rich vacuoles stretch perinuclear cytoplasm (spider cells)
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# CLINICAL ISSUES
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- ## Presentation
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- ### Most common signs/symptoms
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- Obstruction to blood flow → heart failure
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- Arrhythmias
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- Large intracavitary tumors causing turbulent flow → hemolytic anemia & thrombocytopenia
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- May be seen prenatally
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- Generally incidental finding
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- Rarely presents with arrhythmia or hydrops
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- Can detect as early as 22-weeks gestation
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- May discover more masses as pregnancy progresses
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- Tend to ↑ in size prenatally & then regress after birth
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- ## Demographics
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- ### Age
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- 75% are diagnosed before 1 year of age
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- ### Epidemiology
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- Cardiac tumors rare (1:30,000-1:100,000)
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- Rhabdomyoma is most common pediatric cardiac tumor
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- ## Natural History & Prognosis
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- Generally excellent with spontaneous regression in 70% of children by 4 years of age
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- Poor prognosis for untreated large masses interfering with cardiac hemodynamics
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- Most respond well to surgical excision
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- Case reports of response to mTOR (mammalian target of rapamycin) inhibitor sirolimus
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- mTOR: Protein kinase that regulates cellular proliferation; used to treat subependymal giant cell tumors & angiomyolipomas
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- ## Treatment
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- Surgical excision should be considered only for those with refractory arrhythmias or hemodynamic compromise
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- Partial resection of intraluminal component of large exophytic masses may be necessary
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- 3D printing from CT/MR data can build heart model with tumor location & extent for easy visualization; can assist with procedural planning
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- Attempts at electrophysiology testing & ablation around tumor focus have variable success rates
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- 3D printed models have been helpful
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- Small, intramural masses with no hemodynamic effect typically need no treatment or surgical excision
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# DIAGNOSTIC CHECKLIST
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- ## Consider
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- Overall prognosis is excellent
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- However, rhabdomyomas may cause significant morbidity from obstruction to inflow or outflow, ventricular dysfunction, or arrhythmias
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ac7ab661-20c8-405d-97f4-80c98e82f4a7
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## References
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# Selected References
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1. [Tsoumani Z et al: Magnetic resonance imaging of intramyocardial fat deposition in tuberous sclerosis. Diagnostics (Basel). 10(12), 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=33271987%5Bpmid%5D)
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1. [Victoria T et al: Imaging of fetal tumors and other dysplastic lesions: a review with emphasis on MR imaging. Prenat Diagn. 40(1):84-99, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=31925807%5Bpmid%5D)
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1. [Poterucha TJ et al: Cardiac tumors: clinical presentation, diagnosis, and management. Curr Treat Options Oncol. 20(8):66, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31250250%5Bpmid%5D)
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1. [Ugurlucan M et al: Giant rhabdomyoma requiring emergency resection early after birth. Ann Thorac Surg. 107(1):e65, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30009805%5Bpmid%5D)
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1. [Chen J et al: Fetal cardiac tumors: fetal echocardiography, clinical outcome and genetic analysis in 53 cases. Ultrasound Obstet Gynecol. 54(1):103-9, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29877000%5Bpmid%5D)
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1. [Dragoumi P et al: Diagnosis of tuberous sclerosis complex in the fetus. Eur J Paediatr Neurol. 22(6):1027-34, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30279084%5Bpmid%5D)
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1. [Palaskas N et al: Evaluation and management of cardiac tumors. Curr Treat Options Cardiovasc Med. 20(4):29, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29556752%5Bpmid%5D)
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1. [von Ranke FM et al: Imaging of tuberous sclerosis complex: a pictorial review. Radiol Bras. 50(1):48-54, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28298732%5Bpmid%5D)
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1. [Ying L et al: Primary cardiac tumors in children: a center's experience. J Cardiothorac Surg. 11(1):52, 2016](http://www.ncbi.nlm.nih.gov/pubmed/?term=27067427%5Bpmid%5D)
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1. [Sciacca P et al: Rhabdomyomas and tuberous sclerosis complex: our experience in 33 cases. BMC Cardiovasc Disord. 14:66, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24884933%5Bpmid%5D)
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1. [Tao TY et al: Pediatric cardiac tumors: clinical and imaging features. Radiographics. 34(4):1031-46, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25019440%5Bpmid%5D)
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1. [Beroukhim RS et al: Characterization of cardiac tumors in children by cardiovascular magnetic resonance imaging a multicenter experience. J Am Coll Cardiol. 58(10):1044-54, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21867841%5Bpmid%5D)
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1. [Miyake CY et al: Cardiac tumors and associated arrhythmias in pediatric patients, with observations on surgical therapy for ventricular tachycardia. J Am Coll Cardiol. 58(18):1903-9, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=22018302%5Bpmid%5D)
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1. [Tiberio D et al: Regression of a cardiac rhabdomyoma in a patient receiving everolimus. Pediatrics. 127(5):e1335-7, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21464184%5Bpmid%5D)
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1. [Jain D et al: Benign cardiac tumors and tumorlike conditions. Ann Diagn Pathol. 14(3):215-30, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=20471569%5Bpmid%5D)
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1. [Yinon Y et al: Fetal cardiac tumors: a single-center experience of 40 cases. Prenat Diagn. 30(10):941-9, 2010](http://www.ncbi.nlm.nih.gov/pubmed/?term=20721876%5Bpmid%5D)
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1. [Burke A et al: Pediatric heart tumors. Cardiovasc Pathol. 17(4):193-8, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18402818%5Bpmid%5D)
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1. [Syed IS et al: MR imaging of cardiac masses. Magn Reson Imaging Clin N Am. 16(2):137-64, vii, 2008](http://www.ncbi.nlm.nih.gov/pubmed/?term=18474324%5Bpmid%5D)
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1. [Kellenberger CJ et al: Cardiovascular MR imaging in neonates and infants with congenital heart disease. Radiographics. 27(1):5-18, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17234995%5Bpmid%5D)
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1. [Sparrow PJ et al: MR imaging of cardiac tumors. Radiographics. 25(5):1255-76, 2005](http://www.ncbi.nlm.nih.gov/pubmed/?term=16160110%5Bpmid%5D)
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1. [Kiaffas MG et al: Magnetic resonance imaging evaluation of cardiac tumor characteristics in infants and children. Am J Cardiol. 89(10):1229-33, 2002](http://www.ncbi.nlm.nih.gov/pubmed/?term=12008185%5Bpmid%5D)
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1. [Grebenc ML et al: Primary cardiac and pericardial neoplasms: radiologic-pathologic correlation. Radiographics. 20(4):1073-103; quiz 1110-1, 1112, 2000](http://www.ncbi.nlm.nih.gov/pubmed/?term=10903697%5Bpmid%5D)
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## Images
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### Selected Images
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*Axial graphic shows a partially exophytic rhabdomyoma <img src='img/arrows/WC.png'/> in the apex of the left ventricle (LV).*
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*Axial graphic shows a partially exophytic rhabdomyoma <img src='img/arrows/WC.png'/> in the apex of the left ventricle (LV).*
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*Axial T1 MR was performed in an asymptomatic 8-year-old girl with tuberous sclerosis complex (TSC) after a routine screening echocardiogram showed an intracardiac mass. MR shows a round, well-demarcated, intraluminal mass <img src='img/arrows/WS.png'/> originating from the free wall of the LV. It is slightly hyperintense to myocardium, a characteristic finding of rhabdomyomas.*
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*Axial US through the fetal chest shows multiple echogenic, intracardiac masses <img src='img/arrows/WS.png'/> involving both ventricles & the interventricular septum. Multiple rhabdomyomas are virtually diagnostic of TSC.*
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*Axial CECT of the heart in a 15-year-old patient with a history of multiple rhabdomyomas shows complete involution of masses with only small fatty deposits now seen along the interventricular septum, consistent with known TSC.*
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*Four-chamber view from a fetal echocardiogram shows an echogenic mass in the apex of the right ventricle (RV), most consistent with a rhabdomyoma. The patient was later diagnosed with TSC. A mass this size will likely have no physiologic effect on the cardiac function.*
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*Gross pathology of the heart shows a well-defined mass <img src='img/arrows/WS.png'/> arising from the wall of the ventricle. Histology confirmed a rhabdomyoma.*
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*SSFP bright blood cine short-axis MR in a neonate demonstrates a large, hypointense rhabdomyoma <img src='img/arrows/CO.png'/> within the RV wall <img src='img/arrows/CS.png'/>.*
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*SSFP cine short-axis MR in same patient at 13 years of age demonstrates near-complete resolution of the rhabdomyoma with minimal residual tumor <img src='img/arrows/CO.png'/>. The RV <img src='img/arrows/CS.png'/> appears borderline dilated, & the LV <img src='img/arrows/WS.png'/> appears normal.*
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*Postnatal axial US in a patient with tuberous sclerosis shows a large echogenic mass <img src='img/arrows/WS.png'/> filling the LV. Rhabdomyomas are often large at birth but usually spontaneously regress postnatally.*
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*Four-chamber view double IR image from a cardiac MR demonstrates an echogenic mass <img src='img/arrows/WS.png'/> filling the LV, consistent with a rhabdomyoma. Masses of this size may have cardiac obstruction & heart failure. Note the marked enlargement of the heart <img src='img/arrows/CO.png'/> in this neonate.*
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### Additional Images
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*CT-derived 3D-printed heart model demonstrates a rhabdomyoma <img src='img/arrows/CS.png'/> in the LV free wall of a teenager being considered for mass resection due to refractory ventricular tachycardia.*
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*Postnatal echocardiogram in the parasternal long axis shows a large mass <img src='img/arrows/WS.png'/> along the interventricular septum of the LV. Rhabdomyomas may grow during pregnancy but usually spontaneously regress postnatally.*
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*Gross pathology shows a rhabdomyoma <img src='img/arrows/WC.png'/> causing dramatic LV wall thickening. Rhabdomyomas can vary widely in size, number, & morphology.*
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*Echocardiogram in a neonate with TSC shows persistence of multiple echogenic rhabdomyomas <img src='img/arrows/WS.png'/> in the heart.*
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*Four-chamber echocardiogram of the fetal heart shows a right atrial rhabdomyoma <img src='img/arrows/WS.png'/>. This is a far less common location for rhabdomyoma than the ventricles.*
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*Four-chamber fetal echocardiogram shows a large, echogenic solitary tumor <img src='img/arrows/WS.png'/> in the ventricular septum, which makes both the left ventricular <img src='img/arrows/WO.png'/> & RV <img src='img/arrows/WC.png'/> volumes small.*
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*Axial T1 MR of a newborn with an in utero diagnosis of a cardiac mass shows dramatic LV wall thickening <img src='img/arrows/WC.png'/>. The infant was hemodynamically stable. The prognosis for rhabdomyomas is good if there are no complications in utero or in the first 6 months of life (as these lesions regress over time).*
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*Follow-up axial T1 MR in the same patient at 2 years of age shows marked involution of the mass with residual wall thickening.*
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