The patient was 77-year-old man. He visited our hospital with the chief complaint of an abdominal mass in March 2015. We diagnosed the patient with transverse colon cancer and he was suspected of having malignant lymphoma. In March 2016, we attempted to perform right hemicolectomy for the transverse colon cancer, but it was difficult because swollen lymph nodes had formed a large mass with the surrounding tissue, including vessels of the mesentery. We could only complete the surgery after mesenteric lymph node biopsy. On the basis of the results of this biopsy, we diagnosed angioimmunoblastic Tcell lymphoma. At first, we administered THP-COP therapy for malignant lymphoma. However, after 3 courses of this therapy, the patient suddenly developed ileus due to the aforementioned colon cancer. According to enhanced CT performed at the onset of intestinal obstruction, chemotherapy dramatically reduced the size of the intraperitoneal lymph nodes. We therefore concluded that it was able to treat the colon cancer. We performed right hemicolectomy in June 2015. Angioimmunoblastic T-cell lymphoma comprises only 2-3% of all malignant lymphoma cases. We experienced a rare case of complications from angioimmunoblastic T-cell lymphoma and colorectal cancer.