Location: 75%-80% of cardiac myxomas are located in the left atrium, 15%-20% are located in the right atrium, and 10% are either biatrial or in the ventricles. Myxomas most commonly develop from the interatrial septum but can also originate from the posterior and anterior atrial walls or the atrial appendage.
Clinical symptoms are variable and are depend on tumor size, location, and mobility. A classic triad of intracardiac obstruction, extracardiac embolism, and systemic / constitutional complaints has been described.
Most cases arise sporadically. Familial cases have been associated with the occurrence of multiple and atypical tumors. Complex familial tumors are part of a rare condition called the Carney complex. Carney complex may manifest with adrenocortical involvement, pituitary-related symptoms, abnormal pigmentation, or multiple neoplasias in the skin, thyroid, testicles, breast, and neural systems. Heterozygous mutation in the PRKAR1A gene, a protein kinase A regulatory subunit-1-alpha gene, on chromosome 17q22-24 has been linked to cases of intracardiac myxoma and to Carney complex type 1. Carney complex type 2 involves a locus at chromosome 2p16, although the gene responsible remains unknown.
Cardiac myxomas can grow rather quickly. Recurrence is thought to be due to inadequate resection, multicentric growth, inheritance, or metastasis and usually happens during the first 4 years postexcision. Sporadic cases almost never recur, while incidence of recurrence for familial cases, Carney complex, and multiple myxomas are 10%, 22%, and 33%, respectively.
D15.1 – Benign neoplasm of heart
233854003 – Atrial myxoma
Differential Diagnosis & Pitfalls
Benign primary cardiac tumors:
- Papillary fibroelastomas – Second most common benign cardiac tumor; occurs predominately in elderly patients (> 80 years). Usually < 1 cm in diameter, sessile pedunculated tumors attached to the mitral valve or semilunar valves; occurs exclusively on endocardium.
- Rhabdomyomas – Most common cardiac tumor in children. Often multiple masses located in the ventricular myocardium; 50% of cases are associated with tuberous sclerosis.
- Fibromas – Congenital tumors seen in children. Usually solitary, fibrous, and calcified; located in the myocardium.
- Hemangiomas – Highly vascularized.
- Lipomas – Encapsulated tumors usually originating from the epicardium.
- Paragangliomas – Usually benign.
- Atrioventricular node tumor – Located at the base of the atrial septum.
- Angiosarcoma – Highly invasive; usually with evidence of lung, brain, and/or liver metastasis upon diagnosis.
- Rhabdomyosarcoma – Usually diagnosed in children; highly aggressive and may occur in any heart chamber.
- Osteosarcoma – Bulky, sessile tumors usually located in the left atrium.
- Leiomyosarcoma – Highly invasive; sessile masses with mucoid surface.
- Lymphoma – Associated with lymphoproliferative conditions such as AIDS and with immunocompromised patients.
- Metastatic tumors – From direct extension from tumors in the mediastinum; hematogenous or lymphatic spread; more commonly affects the pericardium or myocardium.
- Valvular vegetations
- Right atrial masses – Prominent eustachian valve; Chiari network, aneurysm of the interatrial septum.