[A Case of Malignant Lymphoma Incidentally Diagnosed by Lymph Node Dissection during Gastrectomy].

A 65‒year‒old man was diagnosed with gastric cancer during a detailed examination for anemia and hospitalized for surgery. Laparoscopy‒assisted distal gastrectomy, D1+ dissection, and Billroth Ⅰ reconstruction were performed. The postoperative course was favorable, and he was discharged on postoperative day 8. The histopathological stage of the cancer was pStage ⅠA(T1aN0M0). A malignant lymphoma was found in the dissected No. 3, No. 4d, and No. 8a lymph nodes. He was diagnosed with a large B‒cell lymphoma(Stage Ⅲ)by hematological examination and is currently being administered R‒ CHOP. No gastric cancer recurrence has occurred for 2 years since the surgery. There is no published report on the diagnosis of such a double cancer, ie, malignant lymphoma diagnosed by lymph node dissection during surgery for gastric cancer. We herein report this case with reference to the literature.