Letter to the Editor - Codman's Triangle in Tubercular Osteomyelitis

Sir,
An eight-year-old male child presented with prolonged history of low-grade fever and a progressively increasing swelling on left lower thigh. His grandmother was treated for pulmonary tuberculosis a year back. He had cervical lymphadenopathy, hepatosplenomegaly and bronchial breath sounds and crepitations in right infra-axillary area. The thigh swelling was firm, mobile and tender without erythema or warmth. The movements of the left knee joint were normal. Investigations showed haemoglobin concentration of 7.6gm%, total leucocyte count of 6200/mm³ with polymorphs 73%, lymphocytes 26%, and eosinophils 1%. Erythrocyte sedimentation rate was 125 mm at the end of one hour. Tuberculin test produced 15x20 mm induration. Chest X-ray showed right middle and lower zone consolidation with mediastinal enlargement. ELISA for retrovirus was negative. X-ray of lower end of left femur (Figure) showed anterolateral cortical erosion with subperiosteal new bone formation in the form of Codman's triangle. Medullary bone sclerosis was also seen. Excisional biopsy of swelling revealed epitheloid cell granuloma, caseous necrosis and new bone formation. Stain for acid-fast bacilli were positive and culture grew tubercle bacilli. He was started on anti-tubercular treatment, to which he has clinically responded.