We report a rare case of primary adenocarcinoma in an 82-year-old man that developed 30 years after vesicocutaneostomy was performed to treat pelvic fractures and urethral injury sustained in a traffic accident. He was lost to follow-up after the surgery. However, he presented again at our hospital with gross hematuria. We detected adenocarcinoma at the edge of the vesicocutaneostomy site in the cystoscopic examination and biopsy findings through the stoma. Computed tomography revealed no evidence of metastasis. We conducted radical cystectomy and abdominal wall resection around the vesicocutaneostomy site and ileal conduit formation. Histopathological examination of surgical specimens revealed primary adenocarcinoma of enteric metaplasia origin and skin involvement. The pathological diagnosis was T4b N0 M0 (stage IV) adenocarcinoma of the bladder. In our case, chronic irritation at the stoma was thought to have induced enteric metaplasia of the bladder epithelium and adenocarcinoma. Although the only symptom exhibited was mild gross hematuria, our case was of advanced cancer with skin involvement. Primary adenocarcinoma of the bladder is rare, and only a few cases of adenocarcinoma associated with vesicocutaneostomy have been reported. However, careful examination should be performed to avoid overlooking malignant tumors in cases with bleeding from the vesicocutaneostomy site.