---
title: "Rhabdomyoma"
docid: "2915b0ba-a2fc-425c-beb7-2566dd945aed"
authors:
- key: "7e393d6e-f8be-4315-b1cd-b4639ee57a5f"
value: "Randy R. Richardson, MD"
- key: "db1ca0c5-292f-4acd-847d-c73a4f4ba734"
value: "Ryan A. Moore, MD"
- key: "961f3a7f-ad62-43bc-98f4-5116b17ab812"
value: "Paula J. Woodward, MD, FSRU"
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name: "Pediatrics"
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name: "Rhabdomyoma"
slug: "rhabdomyoma"
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category: "Pediatrics"
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lastUpdated: "10/28/21"
pageDescription: "Rhabdomyoma"
pageKeywords: "Pediatrics, Diagnosis, Cardiac, Miscellaneous, Rhabdomyoma"
pageTitle: "Rhabdomyoma | STATdx"
enhancedTitle: "Rhabdomyoma"
type: "DX"
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breadcrumbs:
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---
# KEY FACTS
- ## Terminology
- Congenital cardiac hamartoma composed of abnormal myocytes
- ## Imaging
- Initial diagnosis is often by fetal &/or postnatal echocardiogram
- Homogeneous, hyperechoic mass(es) of myocardium
- Intramyocardial: May appear as wall thickening
- Intracavitary: Mass attached to myocardium protrudes into lumen
- MR is leading diagnostic test to delineate location, extent, & tissue characteristics of cardiac masses in children
- T1: Iso- or mildly hyperintense to myocardium
- T2: Hyperintense to myocardium
- 1st-pass perfusion: Hypointense to myocardium
- Late gadolinium enhancement: Isointense to myocardium
- Homogeneous appearance on all sequences
- Normal chest radiograph in small masses
- Cardiomegaly & signs of congestive heart failure in large masses
- Image brain (MR) & kidneys (US) for findings of tuberous sclerosis complex (TSC)
- ~ 100% of patients with multiple rhabdomyomas & 50% with single rhabdomyoma have TSC
- ## Top Differential Diagnoses
- Fibroma; pericardial teratoma
- ## Clinical Issues
- Cardiac tumors are rare in children
- Rhabdomyoma is most common pediatric cardiac tumor
- 75% are diagnosed before 1 year of age
- Natural history: Up to 93% show spontaneous regression; 70% regress by 4 years of age
- Surgical excision for minority of cases with refractory arrhythmias or hemodynamic compromise
# TERMINOLOGY
- ## Definitions
- Congenital cardiac hamartoma composed of abnormal myocytes
# IMAGING
- ## General Features
- ### Best diagnostic clue
- Cardiac mass within or contiguous with myocardium
- ### Location
- Interventricular septum > left or right ventricular free wall > > atrium
- Multiple in up to 90% of cases
- ### Size
- < 1 mm to 10 cm; most are 3-4 cm
- ### Morphology
- Well-circumscribed, nonencapsulated mass(es)
- Intramural or exophytic
- May involve entire wall & appear as wall thickening
- ## Radiographic Findings
- Normal chest radiograph in small masses
- Cardiomegaly & signs of heart failure in large masses
- ## Echocardiographic Findings
- Often superior to MR for detection of small masses
- Homogeneous, hyperechoic mass involving myocardium
- No blood flow within mass
- Most often in interventricular septum but can be anywhere
- May appear as simple wall thickening
- Intraluminal portion of mass may move across adjacent valve during cardiac cycle
- ## CT Findings
- ### NECT
- Often hypodense compared with myocardium
- ### CECT
- Intraluminal component may be assessed with contrast-enhanced studies
- ## MR Findings
- ### T1WI
- Iso- or mildly hyperintense to myocardium
- ### T2WI
- Hyperintense to myocardium
- No change with fat saturation (rules out lipoma)
- ### T1WI C+
- Minimal initial enhancement (1st-pass perfusion)
- Isointense to myocardium with late gadolinium enhancement (LGE)
- ### SSFP cine
- Help to differentiate tumor from contractile myocardium, evaluate hemodynamic effect of mass, & look for valvular leak
- ## Imaging Recommendations
- ### Best imaging tool
- Dedicated transthoracic echo in all cases
- MR is helpful for diagnostic uncertainty, large masses, & surgical planning
- ### Protocol advice
- If cardiac mass is identified
- Look for additional masses
- Assess location & quality of mass
- Look for rhythm abnormalities
- Premature atrial or ventricular contractions are common
- Supraventricular tachycardia
- Sinus bradycardia
- Look for signs of obstruction
- Ventricular inflow or outflow obstruction
- May manifest as valve regurgitation or stenosis
- ↑ cardiac work to overcome obstruction → wall hypertrophy
- Evaluate for other findings of tuberous sclerosis complex (TSC)
- In fetus, monitor for signs of hydrops (poor function, effusions)
# DIFFERENTIAL DIAGNOSIS
- [Fibroma](/document/fibroma/8ed96e48-c833-4244-87b3-6c34b6ee34f1)
- Benign congenital cardiac neoplasm composed of fibroblasts & collagen
- 2nd most common cardiac neoplasm in pediatric population after rhabdomyoma
- Often arises from interventricular septum or left ventricular free wall
- MR: Isointense on T1, hypointense on T2
- [Teratoma](/document/pericardial-teratoma/c115823c-1a05-4185-9ce4-774cd0984249)
- Pericardial (not myocardial) tumor
- Exophytic growth (will not be in cardiac chamber)
- Pericardial effusion is often present
- Contains all 3 germ cell layers → may be very heterogeneous on imaging with cystic, fatty, & calcified components
- [Lipoma](/document/cardiac-lipoma/c332f74f-e3cd-47ba-9ff5-5bce83e0e595)
- Most arise from endocardial surface & protrude into chamber lumen
- Fat density/intensity on imaging studies allows for specific diagnosis
- [Myxoma](/document/atrial-myxoma/f9b6c595-ff7b-4731-a799-666983e7f4ed)
- Majority manifest in adulthood (4th-7th decades)
- 90% are solitary & atrial in location
- 75% in left atrium, 10-20% in right atrium
- Predilection for interatrial septum adjacent to fossa ovalis
- [Papillary Fibroelastoma](/document/papillary-fibroelastoma/7081571d-9b34-4b8e-9bfa-d08e375a1919)
- > 90% involve valves
- Typically small (< 15 mm)
- [Cardiac Malignancies](/document/cardiac-sarcomas/62ce81d0-f7c9-4a17-9ccf-6204aff4f62e)
- Extremely uncommon in children
- Sarcomas account for most (with angiosarcoma being most common)
- Usually large masses with invasive features
- Pericardial & pleural effusion are often present
# PATHOLOGY
- ## General Features
- ### Etiology
- Unknown, but data suggests maternal hormones may play role in growth & development of fetal rhabdomyomas
- Helps explain regression after delivery
- ### Genetics
- Nearly 100% of patients with multiple & 50% with single rhabdomyomas have TSC
- TSC: Autosomal dominant with variable expressivity
- ~ 30% of cases are inherited
- Other cases are due to new mutation
- Caused by mutations in *TSC1* or*TSC2* genes
- *TSC1* is located on chromosome 9q
- Encodes for hamartin protein
- Complexes with tuberin to regulate cell cycle
- *TSC2* located on chromosome 16p
- Encodes for tuberin protein
- Participates in normal brain development & cardiomyocyte differentiation
- ### Associated abnormalities
- Other findings of TSC
- Brain: Subependymal nodules, cortical/subcortical tubers, subependymal giant cell astrocytoma
- Lung: Lymphangioleiomyomatosis
- Kidney: Angiomyolipomas & cysts
- Eye: Retinal hamartomas
- Nails: Ungual fibromas
- Pathophysiology
- Mass may interfere with myocardial contraction
- Exophytic masses frequently obstruct blood flow or cause valvular insufficiency
- ## Gross Pathologic & Surgical Features
- Well-circumscribed, intramyocardial or exophytic mass(es)
- ## Microscopic Features
- Large, vacuolated myocytes
- Glycogen-rich vacuoles stretch perinuclear cytoplasm (spider cells)
# CLINICAL ISSUES
- ## Presentation
- ### Most common signs/symptoms
- Obstruction to blood flow → heart failure
- Arrhythmias
- Large intracavitary tumors causing turbulent flow → hemolytic anemia & thrombocytopenia
- May be seen prenatally
- Generally incidental finding
- Rarely presents with arrhythmia or hydrops
- Can detect as early as 22-weeks gestation
- May discover more masses as pregnancy progresses
- Tend to ↑ in size prenatally & then regress after birth
- ## Demographics
- ### Age
- 75% are diagnosed before 1 year of age
- ### Epidemiology
- Cardiac tumors rare (1:30,000-1:100,000)
- Rhabdomyoma is most common pediatric cardiac tumor
- ## Natural History & Prognosis
- Generally excellent with spontaneous regression in 70% of children by 4 years of age
- Poor prognosis for untreated large masses interfering with cardiac hemodynamics
- Most respond well to surgical excision
- Case reports of response to mTOR (mammalian target of rapamycin) inhibitor sirolimus
- mTOR: Protein kinase that regulates cellular proliferation; used to treat subependymal giant cell tumors & angiomyolipomas
- ## Treatment
- Surgical excision should be considered only for those with refractory arrhythmias or hemodynamic compromise
- Partial resection of intraluminal component of large exophytic masses may be necessary
- 3D printing from CT/MR data can build heart model with tumor location & extent for easy visualization; can assist with procedural planning
- Attempts at electrophysiology testing & ablation around tumor focus have variable success rates
- 3D printed models have been helpful
- Small, intramural masses with no hemodynamic effect typically need no treatment or surgical excision
# DIAGNOSTIC CHECKLIST
- ## Consider
- Overall prognosis is excellent
- However, rhabdomyomas may cause significant morbidity from obstruction to inflow or outflow, ventricular dysfunction, or arrhythmias
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## References
# Selected References
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
## Images
### Selected Images
in the apex of the left ventricle (LV).](images/app.statdx.com_image_thumbnail_df742c67-dd2c-43c2-b8e6-b3b6ce98a26a_annotated_true_size_900_quality_90_0b7d73e5da0b5bac5f62ba107fcc23d0880b8df7.jpg)
*Axial graphic shows a partially exophytic rhabdomyoma in the apex of the left ventricle (LV).*
*Axial graphic shows a partially exophytic rhabdomyoma in the apex of the left ventricle (LV).*
originating from the free wall of the LV. It is slightly hyperintense to myocardium, a characteristic finding of rhabdomyomas.](images/app.statdx.com_image_thumbnail_a9b566dd-e465-4183-b9c4-2fad18730a29_annotated_true_size_900_quality_90_723bdc0e46a34b704b81fdbe7a9aa195507fbc71.jpg)
*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 originating from the free wall of the LV. It is slightly hyperintense to myocardium, a characteristic finding of rhabdomyomas.*
*Axial US through the fetal chest shows multiple echogenic, intracardiac masses involving both ventricles & the interventricular septum. Multiple rhabdomyomas are virtually diagnostic of TSC.*
*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.*
*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.*
*Gross pathology of the heart shows a well-defined mass arising from the wall of the ventricle. Histology confirmed a rhabdomyoma.*
within the RV wall 
.](images/app.statdx.com_image_thumbnail_fe84b1d3-a052-4260-92ab-e0fd348fc7a3_annotated_true_size_900_quality_90_8596384db65b34c27ccf1856d54b3df58d7fbf5c.jpg)
*SSFP bright blood cine short-axis MR in a neonate demonstrates a large, hypointense rhabdomyoma within the RV wall .*
*SSFP cine short-axis MR in same patient at 13 years of age demonstrates near-complete resolution of the rhabdomyoma with minimal residual tumor . The RV appears borderline dilated, & the LV appears normal.*
*Postnatal axial US in a patient with tuberous sclerosis shows a large echogenic mass filling the LV. Rhabdomyomas are often large at birth but usually spontaneously regress postnatally.*
*Four-chamber view double IR image from a cardiac MR demonstrates an echogenic mass filling the LV, consistent with a rhabdomyoma. Masses of this size may have cardiac obstruction & heart failure. Note the marked enlargement of the heart in this neonate.*
### Additional Images
*CT-derived 3D-printed heart model demonstrates a rhabdomyoma in the LV free wall of a teenager being considered for mass resection due to refractory ventricular tachycardia.*
*Postnatal echocardiogram in the parasternal long axis shows a large mass along the interventricular septum of the LV. Rhabdomyomas may grow during pregnancy but usually spontaneously regress postnatally.*
*Gross pathology shows a rhabdomyoma causing dramatic LV wall thickening. Rhabdomyomas can vary widely in size, number, & morphology.*
*Echocardiogram in a neonate with TSC shows persistence of multiple echogenic rhabdomyomas in the heart.*
*Four-chamber echocardiogram of the fetal heart shows a right atrial rhabdomyoma . This is a far less common location for rhabdomyoma than the ventricles.*
& RV volumes small.](f2356d8a-e70f-42db-a78d-d94dbd2250b1)
*Four-chamber fetal echocardiogram shows a large, echogenic solitary tumor in the ventricular septum, which makes both the left ventricular & RV volumes small.*
*Axial T1 MR of a newborn with an in utero diagnosis of a cardiac mass shows dramatic LV wall thickening . 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).*
*Follow-up axial T1 MR in the same patient at 2 years of age shows marked involution of the mass with residual wall thickening.*