myxomas

Myxomas are benign mesenchymal tumors characterized by a gelatinous, mucopolysaccharide-rich extracellular matrix called myxoid stroma. They can arise in a variety of tissues, most notably in the heart, skeletal muscle, and jaw. The term covers several distinct entities, including cardiac myxomas, odontogenic myxomas, and soft-tissue myxomas.

Cardiac myxomas are the most common primary heart tumor in adults, though they remain rare. Most occur in the left atrium, often attached near the fossa ovalis by a stalk, but they can arise in other chambers. Symptoms may include obstruction of blood flow, valvular dysfunction, or embolic events; constitutional symptoms such as fever and weight loss can occur. Diagnosis is usually by echocardiography; MRI or CT helps define extent.

Histologically, myxomas consist of scattered stellate or spindle-shaped cells embedded in a loose, gelatinous myxoid matrix rich in mucopolysaccharides. The tumor margins are usually well defined, and the vascularity is variable. Immunohistochemical profiles reflect their mesenchymal origin.

Management requires surgical excision with removal of the tumor and its stalk. In sporadic cases, recurrence is uncommon (a few percent). Recurrence is more frequent in familial forms, notably Carney complex.

Carney complex is a syndrome characterized by multiple cardiac and cutaneous myxomas, pigmented skin lesions, and endocrine tumors, among other features. Affected individuals require ongoing surveillance for new tumors and hormonal abnormalities.

Noncardiac myxomas include odontogenic myxomas of the jaw, which are locally aggressive and may recur after conservative surgery, and soft-tissue or intramuscular myxomas, which are usually slow-growing and treated by excision. Although all myxomas are benign, their location and growth pattern determine potential complications and management.