Case of Isolated Sacral Tuberculosis Diagnosed by Histopathological Examination in a Patient with End-stage Renal Disease: A Pathologist’s Perspective

Isolated sacral Tuberculosis (TB) is an exceptionally rare presentation of osteoarticular TB, often overshadowed by more common spinal involvements and frequently misdiagnosed due to its non specific clinical and radiological features. The authors present a case of a 43-year-old male with End‑Stage Renal Disease (ESRD) on maintenance haemodialysis, who developed progressive low back pain and sacral tenderness without systemic symptoms. MRI of the lumbosacral spine revealed lytic lesions in the sacral vertebrae with surrounding soft-tissue oedema, raising concerns for malignancy or fungal osteomyelitis. Laboratory investigations revealed elevated Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) but were otherwise inconclusive. Due to the patient’s immunocompromised status and atypical imaging findings, a Computed Tomography (CT)-guided sacral bone biopsy was performed. Histopathological examination demonstrated multiple well-formed epithelioid granulomas with central caseation necrosis and Langhans-type multinucleated giant cells, consistent with tuberculous granulomatous inflammation. Ziehl-Neelsen staining revealed Acid-Fast Bacilli (AFB), confirming the diagnosis. Fungal stains and immunohistochemistry for malignancy were negative. The present case highlights the diagnostic dilemma posed by isolated sacral lesions in immunosuppressed patients and underscores the critical role of histopathology in establishing a definitive diagnosis. To the authors knowledge, this is among the few reported cases of isolated sacral TB in a haemodialysis-dependent patient, emphasising its novelty. Early pathological diagnosis enabled timely initiation of anti-tubercular therapy, leading to significant clinical improvement. The present report aims to raise awareness among clinicians and pathologists about considering TB in the differential diagnosis of sacral lesions, especially in high-risk groups advocates for early tissue diagnosis to avoid delayed or inappropriate treatment.