Tuberculous Sacroiliitis Presenting as a Large Gluteal Abscess.

Tuberculous sacroiliitis is a rare form of extrapulmonary tuberculosis. Its nonspecific clinical presentation often leads to delayed diagnosis and treatment, increasing the risk of severe complications such as deformities and functional limitations. We report the case of a 67-year-old male patient who presented with a progressively enlarging gluteal mass and weight loss. Clinical examination revealed a 20 × 20 cm soft, non-tender mass in the right gluteal region, associated with limited joint mobility. Computed tomography (CT) identified osteolytic lesions in the right sacroiliac joint and a collection in the ipsilateral gluteal region, and both lungs showed disseminated micronodules. The collection was drained, and Xpert MTB/RIF (Mycobacterium tuberculosis/rifampicin) assay detected Mycobacterium tuberculosis. The patient received standard antituberculous therapy for 12 months, resulting in clinical improvement. Tuberculous sacroiliitis requires a high index of suspicion, as delay in treatment may lead to chronic pain and impaired mobility.