Isolated anal tuberculosis presenting as an anal fistula in an immunocompetent child

Extra-pulmonary tuberculosis accounts for less than 15% of all tuberculosis cases, while intestinal tuberculosis accounts for less than 1% of extra-pulmonary forms of the disease. Abdominal organ involvement is more common, but extension to the ano-perineal region is extremely rare. We report a case of a 13-year-old child with an anal fistula without any other signs suggestive of tuberculosis. Diagnosis was confirmed by histopathological examination of the excised fistula and a positive GeneXpert test on fistula material. The initial work-up ruled out Crohn's disease and other localizations secondary to tuberculosis, so the patient was put on anti-tubercular drugs. Six months after the start of treatment, the lesion had completely disappeared, and no recurrence occurred after 8 months of follow-up. Tuberculosis should generally be considered in the differential diagnosis of anal and perianal fistula despite the rarity of this location. In most cases, treatment is primarily medical, with surgical intervention reserved for complications such as abscesses or persistent fistulas.