Cardiac Mass
Gregory Kicska, MD, PhD
DIFFERENTIAL DIAGNOSIS
Common
Thrombus
Cardiac Metastases
Less Common
Myxoma
Rare but Important
Sarcoma
Rhabdomyoma
Fibroma
Hemangioma
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Clinical impact is most affected by determination of possible malignancy
Etiology of cardiac masses often cannot be distinguished with imaging
Mass prevalence, coupled with ancillary findings and clinical history, is best tool in generating focused differential
Thrombus is most common cardiac mass
Malignant:benign ratio ˜ 60:1
Metastasis:primary cardiac tumor ratio = 40:1
Primary benign:primary malignant ratio = 3:1
Primary cardiac neoplasm prevalence reported at 1 per 3,000 to 100,000 in autopsy series
Malignant vs. benign
Heterogeneous MR signal is nonspecific and can be seen in benign or malignant neoplasms
Most lesions are T2 hyperintense and T1 isointense to myocardium
Malignant tumors more often have moderate to strong enhancement than benign masses
Multi-chamber involvement or extension into adjacent structures suggest malignant mass
Myxomas (benign) are usually heterogeneous
Pleural or pericardial effusion suggests primary cardiac malignancy or metastasis
In absence of effusion, primary malignancy is less common and metastasis is very uncommon
Right heart mass suggests metastasis
Helpful Clues for Common Diagnoses
Thrombus
MR signal characteristics vary based on age of thrombus
Chronic thrombus T1 and T2 hypointense
Acute thrombus T1 and T2 hyperintense
Thrombus will not enhance on post-Gd images; best determined on subtraction post-Gd images
Enhancement with vessel expansion suggests tumor thrombus
Thrombus will remain dark on delayed enhancement images using long inversion time (500 ms) due to T2* shortening
Signal intensity will decrease when employing gradient echo sequences vs. spin echo due to T2* shortening
Commonly occur adjacent to area of heart wall hypokinesis or wall thinning
Commonly occur in atrial appendages
Associated with history of myocardial infarction or atrial fibrillation
Polypoid thrombi more likely to embolize than smooth peripheral thrombi
Cardiac Metastases
In adults, most commonly lung, breast, lymphoma, esophagus, and melanoma primary
In children, most commonly leukemia, lymphoma, neuroblastoma, Wilms, hepatoblastoma, and sarcoma
Approximately 90% are clinically silent
Autopsy series of cancer patients show prevalence of approximately 7%
Imaging features are variable; diagnosis suggested by history of above malignancies
Helpful Clues for Less Common Diagnoses
Myxoma
LA:RA ratio about 4:1; bilateral (4%), RV (8%)
10% of cases due to autosomal dominant inheritance
Many cases cause pseudo-mitral valve disease
Approximately 50% will prolapse across AV valve
˜ 15% with calcification
Lobulated:smooth contour ratio approximately 3:1
Helpful Clues for Rare Diagnoses
Sarcoma
Most patients are symptomatic, complaining of dyspnea
Most patients present with metastasis
Angiosarcoma most common pathology at 33%
Angiosarcoma most commonly in right atrium
Other sarcoma histologies preferentially intracavitary in left atrium
Commonly occur between 3rd and 5th decades
Lesion morphology is variable ranging from infiltrative to endocardial
Intense heterogeneous contrast enhancement
Heterogeneous, mostly intermediate T1W signal and heterogeneous, mostly high T2W signal
Rhabdomyoma
Most common benign tumor in pediatric population
High T2W signal and intermediate T1W signal
Multiple lesions are often present
Myocardial/intramural location
50% of patients have coexistent tuberous sclerosis
Fibroma
2nd most common benign tumor in pediatric population
Focal bulge, most commonly in ventricular wall, extending toward cardiac lumen
Involved myocardium is hypokinetic
Myocardial/intramural location
Solitary
Calcification common
T1 iso- or hyperintense compared to myocardium
T2 hypointense compared to myocardium
MR and CT contrast enhancement similar to myocardium or nodular peripheral enhancement
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