Two Cases of Colorectal Cancer with Mesenteric Lymph Node Metastasis Derived from Prostatic Cancer

Abstract

[Case 1] An 82-year-old man presented with a 3-month history of defecation difficulty. Preoperative examination revealed prostatic cancer and rectal cancer. The patient subsequently underwent a Hartmann’s operation with D2 lymph node dissection in July 2011. A histopathological examination revealed a “collision” metastatic rectal (cytokeratin-7 negative, cytokeratin-20 positive) and prostatic (cytokeratin-7 and cytokeratin-20 negative, prostate-specific antigen positive) carcinoma in the pararectal lymph node. [Case 2] A 64-year-old man presented with a 2-month history of urinary disorder and constipation. Preoperative examination revealed prostatic cancer and sigmoid colonic cancer with multiple liver metastases. The patient subsequently underwent a Hartmann’s operation with D3 lymph node dissection in July 2017. A histopathological examination revealed a metastatic prostatic (cytokeratin-7 and cytokeratin-20 negative, prostate-specific antigen positive) carcinoma in the lymph node of the mesocolon. We encountered rare cases of metastatic prostatic cancer to mesenteric lymph nodes, with the “collision phenomenon” in one lymph node.