Fetal Cardiac Masses

Also see the section on fetal cardiac rhabdoymyoma

Fetal Primary Cardiac Tumors During Perinatal Period: https://www.sciencedirect.com/science/article/pii/S1875957216302443 

Behram M, Oğlak SC, Acar Z, Sezer S, Bornaun H, Çorbacıoğlu A, Özdemir İ. Fetal cardiac tumors: prenatal diagnosis, management and prognosis in 18 cases. J Turk Ger Gynecol Assoc. 2020 Dec 4;21(4):255-259. doi: 10.4274/jtgga.galenos.2020.2019.0180. PMID: 33274615; PMCID: PMC7726467.

Fetal cardiac tumor: echocardiography, clinical outcome and genetic analysis in 53 cases - Chen - 2019 - Ultrasound in Obstetrics & Gynecology - Wiley Online Library https://obgyn.onlinelibrary.wiley.com/doi/full/10.1002/uog.19108 

Differential diagnosis for fetal cardiac masses:

1. Rhabdomyoma:

   - Most common fetal cardiac tumor, often associated with tuberous sclerosis.

   - Typically benign, composed of striated muscle cells.

   - Often multiple and found in the ventricular walls or interventricular septum.

   - Can regress postnatally.

2. Teratoma:

   - Rare but usually the second most common cardiac tumor.

   - Often located near the base of the heart, commonly the pericardial sac.

   - Contains multiple tissue types (e.g., bone, cartilage, hair), which may be detected on imaging.

   - Can be large and lead to pericardial effusion or compression effects (i.e. Hydrops).

3. Fibroma:

   - A benign tumor of fibrous connective tissue.

   - Usually singular, large, and found within the ventricular walls, especially the left ventricle.

   - May cause obstruction, arrhythmias, or hemodynamic compromise depending on size and location.

4. Hemangioma:

   - A vascular tumor, which can be associated with high-output heart failure due to arteriovenous shunting.

   - May be found within the myocardium or pericardium.

   - Can lead to complications like pericardial effusion or hydrops fetalis if large and highly vascular.

5. Myxoma:

   - Rare in fetuses but more common in adults.

   - Typically arises in the atria, especially the left atrium.

   - May be mobile and can cause obstruction or embolic phenomena.

6. Pericardial Teratoma:

   - A form of teratoma that originates in the pericardial space rather than the myocardium.

   - Can cause significant pericardial effusion or hydrops fetalis due to compression of cardiac structures.

7. Echogenic Intracardiac Focus (EIF):

   - Not a true mass but an echogenic area, often within the left ventricle.

   - Typically represents calcification or microdeposits.

   - Commonly seen in normal fetuses and generally benign.

8. Intracardiac Thrombus:

   - Can occur in cases of fetal arrhythmias, heart failure, or other hemodynamic disturbances.

   - Usually non-tumoral and can appear as a mobile or fixed mass.

   - More likely in cases with coagulopathies or structural heart defects.

9. Cardiac Hamartoma:

   - Very rare, benign overgrowth of normal cardiac tissue.

   - Can be associated with tuberous sclerosis.

10. Metastatic Tumors:

    - Extremely rare in the fetal period, but certain maternal malignancies (e.g., melanoma) can theoretically metastasize to the fetus.

11. Infectious Causes: Certain infections can cause inflammatory lesions in the fetal heart, such as viral myocarditis, which may appear mass-like on imaging.

12. Congenital Cardiac Anomalies: Structural abnormalities, like diverticula or dilated coronary sinuses, may mimic masses.

Diagnosis of fetal cardiac masses often involves detailed imaging through fetal echocardiography, possibly supplemented by fetal MRI, to assess the tumor's size, location, and effect on cardiac function. Genetic testing for conditions like tuberous sclerosis (if rhabdomyoma is suspected), may also be indicated.

Case 1 - Fetal Cardiac Mass

A large, homogeneous cardiac mass arising from the lateral wall of the left ventricle is protruding into the pericardial sac, exerting a mild mass effect on the left atrium and left ventricle without causing chamber obliteration. The left ventricular outflow tract is narrowed but without significant obstruction. A small pericardial effusion is present, with no apparent inflow obstruction. On pathological evaluation post-natally - the mass revealed to be a rhabdomyoma (differential was fibroma).

Case 2 - Mass (hyperechoic) in the LV free wall.

Case 3 - Pericardial Mass (avascular)