Extrapulmonary Tuberculosis Mimicking an Iliac Bone Lytic Lesion: A Case Report.

Lytic bone lesions pose significant diagnostic challenges due to their varied causes, ranging from malignancies to infections and benign conditions. Tuberculous osteomyelitis, though rare in non-endemic regions, remains an important consideration, particularly in patients from high-burden areas. A 35-year-old Sudanese male with a family history of tuberculosis (TB) presented with chronic left iliac pain that did not respond to nonsteroidal anti-inflammatory drugs (NSAIDs). Imaging revealed an expansile lytic lesion with cortical breaching, initially raising suspicion for malignancy. However, a biopsy showed necrotizing granulomatous osteomyelitis, though cultures - including those for Mycobacterium tuberculosis - were negative. Despite the lack of microbiological confirmation, the patient showed clinical and radiological improvement after starting empirical anti-TB therapy. This case highlights the need to consider tuberculous osteomyelitis in the differential diagnosis of lytic bone lesions, even in the absence of positive cultures, especially in individuals from endemic regions. Histopathological evidence of granulomas and a positive response to anti-TB therapy can support the diagnosis when microbiological tests are inconclusive. Greater awareness of this possibility is essential to prevent delays in treatment and unnecessary invasive procedures.