Nodular sarcoid myositis of skeletal muscle diagnosed by fine needle aspiration biopsy. A case report

BACKGROUND: Symptomatic striated muscle involvement in sarcoidosis is rare. Muscle biopsy is usually required for the diagnosis. Fine needle aspiration biopsy (FNAB) has been successfully used in diagnosing soft tissue lesions. To the best of our knowledge, FNAB of sarcoid myositis has not been reported. CASE: A 31-year-old, black female with a history of sarcoidosis presented with an enlarging, painful, left calf mass. Infected thrombi were suspected. FNAB showed numerous loosely arranged epithelioid histiocytes, multinucleated giant cells and skeletal muscle cells. The overall cytologic picture was that of granulomatous myositis. The cytologic features coupled with the patient's history and magnetic resonance imaging findings suggested sarcoid myositis. Subsequent muscle biopsy showing noncaseating granulomata and negative stains for organisms confirmed the diagnosis of nodular sarcoid myositis. CONCLUSION: Nodular sarcoid myositis can be suggested by FNAB cytology in a patient with a past history of sarcoidosis.