[SUCCESSFUL TREATMENT WITH mFOLFOX6 FOR URACHAL ADENOCARCINOMA WITH MULTIPLE LUNG METASTASIS: A CASE REPORT].

We report the case of a 41-year-old man who presented with gross hematuria and a bladder tumor on ultrasonography. Magnetic resonance imaging indicated a possible muscle-invasive bladder cancer or urachal carcinoma. Following transurethral resection of the bladder tumor, histopathological findings revealed an adenocarcinoma similar to colorectal cancer. The patient was diagnosed with an urachal carcinoma in the urinary bladder dome. Since multiple lung metastases were observed on computed tomography, and his serum carcinoembryonic antigen level was 116 ng/dL, his final diagnosis was a stage IVb urachal carcinoma. He received 11 courses of mFOLOX6, and underwent a laparoscopy-assisted partial cystectomy and pelvic lymph node dissection. Pathological examination confirmed negative surgical margins, but remained tumor cells were confirmed. The patient continued mFOLFOX6 treatment for 12 months postoperatively, with no disease progression observed.