The patient was a 90-year-old man. He was referred to our department with a diagnosis of ascending colon cancer after lower gastrointestinal endoscopy for a positive stool occult blood test. Lower gastrointestinal endoscopy revealed a type 1 tumor 30 mm in the ascending colon and a type 3 tumor 50 mm in the cecum. Biopsy revealed Group 5(tub1)for the ascending colon lesion, but Group 2 for the cecum lesion. The patient was clinically diagnosed as having overlapping ascending colon cancer and cecum cancer, and a right hemicolectomy of the colon was performed. Histopathological examination revealed ascending colon cancer and primary malignant lymphoma of the cecum.