A Fall Worth It: Cutaneous Metastatic Deposit of a Distant Colorectal Cancer With Fistula-in-Ano

A seeded fistula-in-ano from a synchronous colon cancer is rare. We report an unconventional case of a 70-year old male who presented with an incidental post-traumatic perianal cutaneous lump following a fall. Lesion biopsy confirmed the presence of a cutaneous malignant deposit. Further workup confirmed the diagnosis of upper rectal adenocarcinoma associated with a fistula-in-ano. The patient underwent long-course neoadjuvant chemoradiotherapy, followed by an “en bloc” laparoscopic abdominoperineal and extended fistula tract resection without complication. This case highlights a rare case of post-traumatic synchronous upper rectal cancer seeding into a low fistula-in-ano tract associated with a cutaneous perianal metastatic deposit.