Pitfalls and Pearls for Diagnosis of a Child with Tuberculosis Osteomyelitis Masquerading as Brodie's Abscess: A Case Report.

Tuberculous osteomyelitis is an uncommon manifestation of extrapulmonary tuberculosis in children, with diaphyseal involvement being particularly rare. Its insidious course and nonspecific imaging often lead to misdiagnosis as pyogenic osteomyelitis or Brodie's abscess, resulting in delayed treatment. This report highlights a diagnostically challenging case of paediatric tibial tuberculosis osteomyelitis mimicking Brodie's abscess. A 15-year-old girl presented with an 18-month history of chronic pain, swelling, and a draining sinus on her left lower leg. Despite undergoing multiple surgeries and a prolonged course of anti-tuberculous therapy, symptoms persisted. Radiographic and MRI findings suggested Brodie's abscess with diaphyseal and metaphyseal involvement. However, biopsy revealed granulomatous inflammation, and polymerase chain reaction (PCR) testing confirmed Mycobacterium tuberculosis. Subsequent treatment led to clinical improvement and radiological bone union at six-month follow-up. The case underscores the diagnostic difficulty in distinguishing TB osteomyelitis from subacute pyogenic infections, especially in children. Classical radiologic features such as sclerotic rims, lytic lesions, and periosteal reaction are often indistinguishable. FNAB and pus cultures may yield inconclusive results. In this case, PCR was pivotal for definitive diagnosis. Misdiagnosis can lead to inappropriate treatment and unnecessary surgical interventions. Tuberculosis should be considered in the differential diagnosis of chronic osteomyelitis, particularly in TB-endemic regions. Early use of molecular diagnostics such as PCR, along with histopathology, is critical for accurate diagnosis. A multidisciplinary approach facilitates timely intervention, prevents complications, and improves outcomes.