Neurothekeoma in the upper extremity: magnetic resonance imaging and computed tomography findings.

Neurothekeomas are rare benign tumors of soft tissue that are of presumed neural sheath origin. This report describes the magnetic resonance imaging and computed tomography features of a neurothekeoma in the left forearm of a 38-year-old woman with a 2-year history of a painful mass. Magnetic resonance imaging showed a smooth-bordered ovoid lesion within the inner portion of the extensor digitorum muscle with a Hounsfield number of 15. The lesion had intermediate signal on T1-weighted images, high signal on T2-weighted images, and mild to moderate heterogeneous gadolinium contrast enhancement.