Complex microsurgical perineal reconstruction after resection of a giant verrucous carcinoma associated with anal fistulas in Crohn’s disease—a unique case report

BACKGROUND: Crohn’s disease (CD) is a chronic inflammatory disorder which leads to anorectal fistulas. In rare cases, patients develop anal squamous cell carcinoma (ASCC) within these lesions. There is limited literature regarding ASCC in patients with CD. Here, we report on a unique case of advanced verrucous carcinoma (VC), a rare variant of squamous cell carcinoma, developing on the grounds of extensive chronic anorectal fistulas in CD. METHODS AND RESULTS: A 54-year-old male patient with a 20-year history of CD presented with a large inflammatory tumor at the perineal region with multiple discharging perianal fistulas. Histopathological analysis of the perineal mass revealed a VC. Subsequent surgery with radical tumor resection and terminal colostomy resulted in a large perineal cavity and a partially exposed sacrum. The defect extended to a total of 35 × 25 × 25 cm. Reconstruction was achieved through a two-step approach. A first surgical step established an arteriovenous (AV) loop in the upper thigh. Subsequently, a free latissimus dorsi (LD) myocutaneous flap was harvested and anastomosed with the AV loop, allowing for satisfactory closure of the defect and reconstruction of the perianal and perineal region. CONCLUSION: Radical surgical excision with negative margins is the therapy of choice for VC. This case report demonstrates a curative treatment option with special emphasis on the reconstructive possibilities of a unique case of extended perianal and perineal VC associated with chronic anorectal fistulas in CD.