Cardiac tumors

Primary cardiac tumors

• Rare

• Most- benign

• Common benign tumors:

  • No malignant potential

  • Account for ~90% of all primary heart tumors

  • Descending order of frequency:

    • Myxomas

    • Fibromas

    • Lipomas

    • Papillary fibroelastomas

    • Rhabdomyomas

• Primary malignant tumors of the heart- exceedingly rare

• Types:

  • Angiosarcoma

Myxomas

• 50% of primary tumors of the heart

• Sporadic: middle-aged females, in the left atrium, single without associated conditions

• Familial: young people, slightly more in males, less commonly in left atrium, multicentric in one-third of cases, associated with extracardiac abnormalities in 20% of cases

Carney’s syndrome

• myxoma, adrenocortical nodular dysplasia associated with Cushing’s syndrome, Sertoli cell tumor of testis, fibroadenomas

Left sided myxomas

present with signs of mitral stenosis or insufficiency

Right sided myxomas

present with dyspnea, syncope, neck vein distention, and emboli with possible infarcts

Myxomas, Gross

• soft, polypoid, pale lobulated masses, often with a stalk attached to the septum or foramen ovale; calcification may occur.

Myxomas, Microscopically

• round, polygonal, or stellate cells in a loose stroma with acid mucopolysaccharides, mitoses, and pleomorphism are absent

• Arise from multipotent stem cells

• Surgical excision is often curative, and some may recur

Papillary fibroelastoma

• Small papillary (“sea-anemone–shaped”) endocardial tumor

• Occur on surface of valves or other endocardial locations

• Usually, incidental finding at surgery or autopsy

  • Can embolize 🡪 become clinically important

Papillary fibroelastoma- Gross morphology

• >80% located on valves

• 1-2 cm in diameter

• Distinctive cluster of hairlike projections up to 1 cm in length

• - Delicate fronds (become apparent when floating in clear liquid)

Papillary fibroelastoma- Histology

• Papillary projections:

  • Covered by a surface endothelium 

  • Surrounding a core of myxoid connective tissue with abundant mucopolysaccharide matrix and elastic fibers

• Excised from an aortic valve: a central stalk with radiating fronds of avascular fibroelastic tissue, lined by endocardium

Rhabdomyoma

• Most seen during the first decade of life, many are congenital

• It may present in adults, some of whom have tuberous sclerosis or congenital heart disease

• They tend to regress during later infancy and childhood

• One or more firm, well-circumscribed nodules

• Microscopic features: spider cells which have radial cytoplasmic extensions

Rhabdomyomas is the most frequency

• primary tumor of the pediatric heart

  • Discovered in the first years of life during an evaluation for a valve or other flow obstruction

• May regress spontaneously

Rhabdomyomas- Gross morphology

• Gray-white myocardial masses

• Small or up to several cm in diameter

• Multiple 

• Involve the ventricles preferentially

  • Protruding into the lumen

• Gross appearance of cardiac rhabdomyoma. Multiple rhabdomyomas ( arrows ) in a child with Tuberous Sclerosis (at autopsy).

Rhabdomyomas - Histology

Bizarre, markedly enlarged myocytes with large collections of glycogen

• Routine histologic processing removes glycogen

• Artifactually reduces abundant cytoplasm to thin strands that stretch from the nucleus to the surface membrane- appearance referred to as spider cells

Cystic tumor of the atrioventricular nodal region

• Developmental abnormality of epithelial nature and endodermal origin

• It may be associated with other congenital abnormalities

• May result in complete heart block

• Tumors are rarely seen as grossly

• Microscopically have ductal structures, cysts, and solid nests of epithelial-like cells which, on electron microscopy, show desmosomes and microvilli

Sarcoma

• Very rare

• Some may be highly pleomorphic and difficult to classify

• Angiosarcomas are the most common type of sarcoma

• Usually, a large mass in the right atrium

Different types of Sarcoma

• Kaposi sarcoma

• Leiomyosarcoma

• Rhabdomyosarcoma 

• Osteosarcoma

Sarcoma

• Fibrosarcoma 

• Most patients with cardiac sarcomas present with CHF , arrhythmias, or superior vena cava obstructions 

• Malignant tumors are more commonly found on the right side of the heart.

Metastatic tumors

• More common than primary tumors

• Any portion of the heart can be involved 

• If the conduction system is involved, it can result in heart block

• Usually, the primary is in the thoracic or contiguous regions

• Tumor reaches the heart by spreading to the mediastinal lymph nodes

• Tumors that reach the heart via the hematogenous route include melanoma, kidney cancer, breast cancer, and choriocarcinomas