Isolated muscular sarcoidosis mimicking a tumoral lesion

We report a case of a woman with a palpable painful nodule on her left leg. MR and CT showed a lesion that could be described as a neoplasm. Excisonal biopsy revealed a noncaseating granuloma. The woman presented the nodular type of muscular isolated sarcoidosis. Further the disease involved the lungs; this confirmed the accurate diagnosis of sarcoidosis. Sarcoidosis is a chronic, multisystem granulomatous disease of unknown etiology. Muscle involvement is frequent, but often asymptomatic. There are three forms of muscular sarcoidosis: only the nodular type can be recognized by technical imaging. MR and ultrasound are the best methods to attempt the diagnosis of nodular muscular sarcoidosis; nevertheless, the lesion must have a standardized behaviour because it can mimic a malignant neoform. In this case, biopsy is the only tool to identify the disease.