Pseudo-tumoral left-colonic tuberculosis causing acute large-bowel obstruction: a case report and review of the literature.

Introduction and importance: Gastrointestinal tuberculosis predominantly affects the ileocecal region, while isolated left colonic involvement remains rare. Its nonspecific clinical, radiological, and endoscopic features frequently mimic colorectal cancer or inflammatory bowel disease, making diagnosis challenging. Acute large bowel obstruction secondary to left colonic tuberculosis is uncommon and may necessitate emergency surgery before a definitive diagnosis is made. Histopathological examination remains essential for confirmation, and early recognition allows prompt anti-tuberculous treatment with favorable outcomes. We report a rare case of left colonic tuberculosis presenting as acute colonic obstruction mimicking colorectal malignancy. Case presentation: A 30-year-old woman with no significant past medical history presented with colonic obstruction after 6 months of diffuse abdominal pain. CT imaging revealed a stenosing thickening of the sigmoid colon causing large-bowel obstruction, initially suggestive of colorectal malignancy (Fig. 1). The patient underwent a proximal diverting colostomy followed by an oncologic sigmoid colectomy with primary anastomosis (Fig. 2). Histopathological examination of the surgical specimen established the diagnosis of colonic tuberculosis (Fig. 3). Anti-tuberculous therapy was initiated, with a favorable clinical outcome after 1 year of follow-up. Clinical discussion: Colonic tuberculosis is a rare form of gastrointestinal tuberculosis, with isolated left-sided involvement being exceptionally uncommon. Its clinical presentation is nonspecific and may mimic colorectal cancer, inflammatory bowel disease, or diverticulitis, making diagnosis challenging. Acute large-bowel obstruction is a particularly rare presentation and often necessitates emergency surgical management before a definitive diagnosis is established. Radiological findings are not specific and frequently overlap with those of colorectal malignancy. Histopathological examination remains the gold standard for diagnosis, although preoperative confirmation is often difficult in pseudotumoral forms. While anti-tuberculous therapy is the cornerstone of treatment, surgery is indicated in complicated cases such as obstruction or when malignancy cannot be excluded. This case emphasizes the importance of considering colonic tuberculosis in the differential diagnosis of left-sided colonic strictures and acute bowel obstruction, especially in endemic areas, to enable early diagnosis and appropriate management. Conclusion: Left colonic tuberculosis is a rare cause of acute colonic obstruction that can mimic colorectal cancer. Because clinical and imaging findings are nonspecific, diagnosis is often delayed. Histopathology is essential for confirmation, and early diagnosis enables prompt anti-tuberculous treatment and helps avoid unnecessary surgery.