An 88-year-old man was referred to our hospital for further examination of an asymptomatic liver tumor. MRI showed low-intensity regions on T1-weighted images, high-intensity regions on T2-weighted images, high-intensity regions on diffusion-weighted images, and low-intensity regions in the arterial, portal, and hepatocyte phases of Gd-EOB-DTPA. PET scan of the tumor was positive, while endoscopy exhibited no malignant findings. The CT and MRI findings showed that the tumor could be a metastatic liver tumor, cholangiocellular carcinoma, or hepatic inflammatory pseudotumor. Considering the possibility of a malignant tumor, laparoscopic partial hepatectomy was performed as a diagnostic treatment. The patient was discharged on the 8th postoperative day. The histopathological diagnosis was diffuse large B-cell lymphoma. Since the lesion was localized to the liver, a diagnosis of malignant lymphoma originating from the liver was made. Six courses of R-THP-COP therapy were administered. No indication of recurrence was noted 18 months after surgery. Although primary hepatic lymphoma is difficult to diagnose, laparoscopic hepatectomy allows for an accurate diagnosis and early postoperative recovery, enabling rapid administration of chemotherapy.