Intraoperative detection of calculi in a chronic fistula-in-ano: an uncommon finding in a common condition—a case report

Background Fistula-in-ano is a common anorectal condition; however, the incidental presence of calculi within the tract is exceedingly rare, with very few cases described in medical literature. Understanding this atypical occurrence is vital for improving diagnostic and intraoperative decision-making. Case presentation A sixty-two-year-old, non-diabetic male presented with a chronic fistula in Ano with pus discharge. Due to the unavailability of MRI fistulography, diagnosis relied on clinical assessment and digital rectal examination, which revealed a firm, stony mass within the tract.The patient underwent fistulectomy, and the histopathology report revealed lymphoplasmacytic infiltration along the fistula tract. The patient was discharged without postoperative complications. Intraoperatively, and during fistulectomy, calculi were found in the fistulous tract. The patient had an uneventful postoperative course, and the wound healed over 6 weeks. Conclusion This rare finding did not necessitate a change in surgical strategy, and the patient experienced uneventful healing. Calculi, although rare, may be clinically silent and should not delay treatment.