The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis.