Perianal mucinous adenocarcinoma (MAC) is a rare malignancy arising in the anal canal, often associated with chronic inflammatory conditions such as perianal fistulas. This case series aims to elucidate the clinical features and surgical management of patients with perianal MAC arising from perianal fistulas.

Four cases of perianal MAC are presented, highlighting the diverse clinical presentations, diagnostic pathways, and therapeutic interventions. Each case demonstrates unique aspects of disease progression, treatment response, and long-term outcomes. Key features include the challenges of diagnosing MAC amidst benign conditions, the role of neoadjuvant chemotherapy in improving resectability, and the importance of individualized surgical approaches.

All patients were male and presented with a variety of symptoms ranging from changes in bowel habits to perianal abscesses. The diagnosis was challenging due to the resemblance of MAC to benign conditions and delayed presentation. All patients underwent abdominoperineal resection (APR) and colostomy insertion (perineal or abdominal). Two cases required reconstructive procedures where a V—Y flap and an omental flap were employed. A multidisciplinary approach ensures that patients receive appropriate neoadjuvant and adjuvant treatment. With the median follow-up of 3 years, all patients were alive.

Our multidisciplinary approach effectively managed perianal MAC by integrating surgical techniques, including APR and reconstructive methods, along with neoadjuvant and adjuvant treatment. Performing appropriate surgical techniques leads to tumor-free margins, in addition to systemic therapy, and improves both patient survival and quality of life.