Isolated tubercular pseudotumour of lateral malleolus.

A 22-year-young adult presented with a painless swelling of distal fibula on right side for 3-month duration. He had no constitutional symptoms and there was full range of painfree ankle movement. Radiographs showed cortical breech with an osteolytic lesion in lateral malleolus. Magnetic Resonance Imaging showed T2W hyperintense signal in the distal fibula. It further revealed involvement of tendo Achilles and paroneal tendons. Fine needle aspiration cytology showed epitheloid granuloma and Langhans giant cells. The Mycobacterium tuberculosis DNA could be identified on polymerase chain reaction. The patient received 18 months of antitubercular treatment and the lesion subsided. There is no recurrence even after 3 years of follow up. A strong suspicion of tuberculosis should be considered in any bony swelling of a patient from endemic area, even at atypical sites. Polymerase chain reaction analysis should be performed in addition to radiological and histological examination of the lesion to establish the diagnosis. Early treatment with antitubercular therapy decreases the morbidity and avoids the possibility of surgical intervention.