Proliferative myositis: a rare pseudosarcoma of the chest wall.

Proliferative myositis is a rare, inflammatory tumor that is often misdiagnosed as sarcoma. The clinical course of proliferative myositis is benign, and local recurrence after simple excision is uncommon. Typically, the lesion presents in the extremities or the head and neck. We present an unusual case of proliferative myositis with involvement of the anterior chest wall.