COMPLEX PERIANAL FISTULA DUE TO ANORECTAL TUBERCULOSIS

Case Presentation A 46-year-old male patient presented to the coloproctology service after a perianal abscess episode, occurring three months after an infection. At the time, he had an ulcerated external opening approximately 2x2 cm at the 3 o'clock position, with elevated and hardened edges and a small amount of purulent secretion. Colonoscopy, pelvic MRI, and biopsy of the lesion were requested. The biopsy revealed tissue consistent with a perianal fistula, showing non-caseating granulomas containing multinucleated giant cells and epithelioid cells, suggestive of Crohn's disease. A month later, the patient returned to the clinic with continued secretion and the ulcerated lesion. He also reported a history of imprisonment. A perianal fistula caused by tuberculosis was suspected, and twenty days later, a new biopsy and Xpert gene testing for *Mycobacterium tuberculosis* were performed. The new biopsy confirmed the presence of a perianal fistula caused by anorectal tuberculosis, with low bacillary load and sensitivity to Rifampicin.

Discussion Perianal tuberculosis is more common in men, with fistula being the most frequent symptom. A long onset period, recurrences, and a history of prior pulmonary disease suggest the diagnosis. Typical histology shows giant cell granulomas with areas of caseous necrosis; however, caseous granulomas are not always present, which complicates differentiation from Crohn's disease. Complete remission of the condition is achieved with the institution of effective and targeted clinical treatment.

Conclusion Most cases have a good outcome, but it remains a subdiagnosed condition. Therefore, it is crucial that cases like this are reported, along with their outcomes.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025