A RARE CASE OF CIRCUMFERENTIAL ANORECTAL TUBERCULOSIS PRESENTING AS A NON-HEALING ANORECTAL ULCER

Abstract

Background: Background: Anorectal tuberculosis is an exceedingly rare form of extrapulmonary tuberculosis (TB) that can mimic Crohn’s disease, anal fissure, fistula-in-ano, or malignancy, making its diagnosis challenging. A high index  of clinical suspicion,  particularly  in patients with  a history  of TB  exposure,  is  essential  for timely diagnosis and treatment. Case Presentation: A 37-year-old woman with a positive TB contact history and a history of treated pulmonary tuberculosis  three  years  earlier  presented  with  a  painful,  non-healing  anal  ulcer  of  six  months ’  duration associated with bleeding per rectum. She had a known psychiatric illness(Bipolar disorder diagnosed 10 years ago)   on irregular medication. Examination revealed a well-circumscribed, 4 cm non-healing ulcer extending deep to the anal canal. MRI of the pelvis demonstrated a trans-sphincteric blind-ending sinus tract without mesorectal or pelvic lymphadenopathy.Colonoscopy reported no significant changes in rest of bowel. Results: Edge wedge biopsy revealed granulomatous inflammation with focal necrosis; Ziehl–Neelsen, PAS, and GMS  stains  were  negative.  Cartridge-based  nucleic  acid  amplification  testing  (CBNAAT)  detected Mycobacterium tuberculosis with a low probability of rifampicin resistance, confirming anorectal tuberculosis. The  patient  was  started  on  a  first-line,  multidrug  anti-tubercular  therapy  (ATT)  regimen  with  adjunctive sitz-bath and supportive wound care. Conclusion:  Chronic, non-healing  anorectal ulceration  in  a patient with  TB  exposure warrants  systematic evaluation combining clinical, radiological, histopathological, and molecular diagnostics. The integration of biopsy and CBNAAT permits rapid, specific diagnosis with concurrent drug-resistance profiling, enabling early, appropriate ATT and improved outcomes in this rare presentation of extrapulmonary tuberculosis.