Fine needle aspiration cytology of focal myositis: a case report

Focal myositis is an unusual inflammatwy lesion of the skeletal muscle first described by Heffizer. It is a benign condition and usually involves the muscles of the limbs.

A man presented with a palpable mass in the left leg of 6 months' duration. Nuclear magnetic resonance of the leg showed a mass in the tibial muscle; the presumptive diagnosis was sarcoma of the muscle. Smears showed inflammatory cells, skeletal muscle fibers with degenerative and regenerative changes, and fibrous tissue, suggesting a diagnosis of focal myositis. An incisional muscle biopsy was performed, confirming the diagnosis.

Focal myositis should always he considered when aspirating muscle masses because it is a clinical mimic of a neoplasm. The prognosis is good, and all cases reported in the literature were self-limiting and gradually resolved.