Intramuscular composite hemangioendothelioma: case report of an unusual tumor in an unusual location

Composite hemangioendothelioma (CHE) is an extremely rare locally aggressive vascular neoplasm comprising various benign, intermediate, and malignant vascular components. It is usually located superficially, in the dermis and subcutis of the extremities. Herein, we report a first case of CHE arising from the skeletal muscle in a 67-year-old woman who presented with a palpable mass on her right forearm. Magnetic resonance imaging revealed a 3.0 × 2.7-cm intramuscular mass with high-signal intensity on contrast-enhanced T2-weighted images. Excision was performed, and microscopic examination revealed a heterogeneous mixture of vascular components, consisting of arteriovenous malformation, spindle cell hemangioma, retiform hemangioendothelioma, and angiosarcoma-like areas. Moreover, we present a brief review of previously reported cases of CHE arising from the extremities.