Primary tuberculosis of the fibular diaphysis: A rare case report

Primary diaphyseal tuberculosis has very low occurrence. With no systemic signs and specific radiographic features, there exists low index of suspicion, which may delay the diagnosis of tuberculosis.

A female aged 15 years presented with chronic leg pain and swelling for past 7 months. There was no significant history of tuberculosis present. On investigations ESR was 44 mm and positive mantoux test. Chest radiograph was normal. On x-ray (R) fibula intramedullary eccentric lytic lesion and on MRI (R) leg intramedullary lytic lesion was present suggestive of ewing's sarcoma. On histopathology epitheloid granulomas with langhans giant cells were present. Category 1 antitubercular drug regimen was started and lesion healed with alleviations of signs & symptoms.

Tuberculosis presents with typical signs and symptoms in adults compared with children in whom cystic tubercular lesions in shaft of long bones presents mostly as a single solitary intramedullary lytic lesion on MRI, which corresponds with other more common differentials. This clinical and radiological heterogeneity warrants lesional biopsy and culture to determine the right diagnosis to aid in early starting of correct treatment and recovery of the patient.

With atypical presentation of diaphyseal tuberculosis in children, a high index of suspicion with unexplained pain and swelling of the bone could help to establish the diagnosis.