A Case of Rectal Cancer with Lymph Node Metastasis of Prostate Cancer in the Mesorectum after Radical Prostatectomy

Abstract

A case of rectal cancer with lymph node metastasis of prostate cancer in the mesorectum after radical prostatectomy is presented. The patient was a 67-year-old man who underwent robot-assisted laparoscopic prostatectomy for prostate cancer. Postoperatively, biochemical recurrence was observed, and the patient was treated with a gonadotropin-releasing hormone (GnRH) antagonist. A fecal occult blood test led to the finding of a circumferential type 2 tumor in the rectal RS, and biopsy examination showed adenocarcinoma. A laparoscopic high anterior resection with D3 lymph node dissection was performed, and lymph node metastasis of prostate cancer was observed in the mesorectum. The prostate gland has a large inflow of lymphatic vessels, which generally flow into the obturator, internal iliac, and external iliac lymph nodes. Only 17 cases of prostate cancer metastasizing to the mesorectum have been reported in the past. Therefore, this case is considered to be an extremely rare case. It is known that biochemical recurrence is frequently observed in high-risk cases of prostate cancer, and it could be possible that micrometastasis outside the lymph node dissection area was present before the prostate-specific antigen (PSA) was elevated.