Clinical Images: Third time's the charm: a challenging diagnosis of tuberculous trochanteric bursitis

The patient, a 74-year-old man, presented with mechanical pain in left hip. He had previously undergone physiotherapy, which was discontinued five months earlier following suspicion of a gluteal hematoma. He also reported a 9-kg weight loss over a year. Pelvic x-ray revealed erosions of the left greater trochanter (Figure 1A). Magnetic resonance imaging of the left hip and thigh showed a poorly defined collection contiguous with the erosion, extending to the lesser trochanter, with a thickness of 11 mm (Figure 1E and 1F: T1 fat-saturated and T1 weighted image, respectively), and a second multiloculated collection 15 cm in length (hyperintense in a coronal STIR1 sequence; Figure 1D), suggesting a chronic infectious process. Laboratory tests revealed elevated erythrocyte sedimentation rate (56 mm/h) and C-reactive protein (3.12 mg/dL) and a positive interferon-γ release assay. An initial ultrasound-guided aspiration attempt was unsuccessful, yielding only sterile lavage fluid, and a computed tomography–guided bone biopsy was inconclusive. Persistent clinical suspicion of infection led to ultrasound-guided biopsies of both collections (Figure 1B). Histopathologic evaluation of the synovial revealed necrotizing granulomas with peripheral epithelioid cells (Figure 1C) and some Langhans multinucleated cells (Figure 1G, arrow). Cultures subsequently confirmed drug-susceptible Mycobacterium tuberculosis, and quadruple treatment was started. HIV serology was negative. This case highlights the diagnostic value of ultrasound-guided biopsy as a minimally invasive, reliable, and flexible diagnostic tool in the evaluation of indeterminate musculoskeletal lesions. Written informed consent was obtained from the patient for the publication of this image. Disclosure form. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.