Intramuscular Epithelioid Sarcoma Presenting as Extrinsic Flexor Tightness in the Forearm.

Epithelioid sarcoma is an uncommon soft tissue sarcoma involving predominantly the distal extremities of adolescents and young adults. Its rarity makes it difficult to diagnose accurately and treat properly in the early stages. We discuss the delayed diagnosis of a 37-year-old man who presented with extrinsic flexor tightness of the wrist and fingers. We initially thought that the lesion resulted from inflamed soft tissue of the flexor muscles causing contracture. However, histological examination of a biopsy specimen revealed nodular proliferation of epithelioid and spindle cells, which were immunoreactive to epithelial and nonepithelial markers, respectively, leading to the final diagnosis of epithelioid sarcoma.