Abstract
We report a case of a 76-year-old man, who visited another hospital due to a persistent bloody stool during the previous 6 months. The colonoscopy revealed two type-2 cancers on the sigmoid colon and the lower rectum (Rb). A mediastinal lymph node was found to be enlarged and positron emission tomography indicated high uptake in the mediastinal lymph node and a retroperitoneal mass (left pararenal area). We diagnosed it as double cancer of the sigmoid colon and Rb with a mediastinal lymph node metastasis and retroperitoneal tissue metastasis (M1). At the time of surgery, the mediastinal lymph node dissection was performed first, and the frozen section diagnosis was not metastasis but lymphoma, therefore the retroperitoneal mass and rectal resection were resected by lymphadectomy with a transverse colostomy. Histopathological findings showed a diffuse large B-cell lymphoma of the mediastinal lymph node and the left pararenal area. Such a case is rare, so we report with a review of some of the literature.
