Sonographic appearance of an intramuscular myxoma of the pectoralis major muscle.

Intramuscular myxomas are benign soft tissue tumors that usually involve skeletal muscle of the extremities; occurrence in the chest wall is extremely rare. We describe a case of intramuscular myxoma in the pectoralis major muscle of a 55-year-old woman. The patient presented with a palpable lump in her right breast. Mammography showed a circumscribed, oval, hyperdense mass within the pectoralis muscle. Ultrasonography showed a circumscribed, oval, complex mass within the pectoralis muscle.