Intramuscular Schwannoma

34-year-old female with a history of a palpable abnormality in the posteromedial right thigh. Images demonstrate a circumscribed STIR hyperintense, T1 slightly hypointense lesion without signal dropout on the out of phase images. The lesions is bright on the diffusion weighted images, and there is avid enhancement on the postcontrast images. Intramuscular myxoma was favored given the imaging characteristics, but on biopsy, this was found to represent an intramuscular schwannoma. Schwannomas, or benign peripheral nerve sheath tumors, are composed of encapsulated Schwann cells. Typical age of presentation includes middle-aged adults with no gender predilection. Presenting symptoms include a slowly growing, painless lesion which typically arises along the flexor surfaces in the extremities. Intramuscular schwannomas typically originate from a small nerve branch within the muscle. Enucleation is the standard treatment procedure.