Mucinous adenocarcinoma arising in an anorectal fistula

Abstract

Mucinous adenocarcinoma in association with chronic anal fistula is a rare case in clinical practice. The aim of this article was to report a rare case of anal gland mucinous adenocarcinoma in a patient who was treated in the Hospital of Kaunas University of Medicine. A 70-year-old male was treated for anorectal fistula in the surgical department. Four operations were performed for perineal abscess during the period of 15 years. During the period of 15 years, the patient complained of purulent secretion from the perineal abscess. After the last operation, anorectal fistula developed. Multiple biopsies and scrapings of the fistulous track were taken for histological examination. Histological examination revealed mucinous adenocarcinoma, G2. Subsequently, the patient underwent endoanal ultrasound, computed tomography scan, and colonoscopy. The computed tomography scan did not show pathology in the abdomen, but showed soft tissue induration at the site of anorectal fistula. Colonoscopy investigation did not show any pathology in the rectum and bowels. Endoanal ultrasound findings showed soft tissue induration at the site of anorectal fistula, no tumor in the rectum wall. The patient underwent abdominoperineal resection. Histological examination after abdominoperineal resection revealed anal duct mucinous adenocarcinoma pT2 N0 L0 V0 R0, G2. Metastases to the mesenteric lymph nodes were not detected. On the eighth day after abdominoperineal resection, the patient was discharged from the hospital for follow-up. Mucinous adenocarcinoma in anorectal fistula is a rare condition. If surgical treatment for perineal abscess or anorectal fistula is not successful for a long time, mucinous adenocarcinoma should be suspected.