A very unusual clinical presentation of non-Hodgkin's lymphoma (NHL) of the liver is reported herein. The patient was a 35-year-old male who had been HIV-positive since 1987. Following an episode of acute pain in the right upper abdominal quadrant, ultrasonography (US) and computed tomography (CT) were performed, revealing a nodular lesion, 2.5 cm in diameter, localized in the eighth segment of the liver. Despite the fact that the lesion became significantly enlarged over a 6-month period, three repeated percutaneous biopsies proved negative. Finally, his increasing pain and the lack of a definitive diagnosis prompted us to perform a right hepatectomy. The patient had an uneventful postoperative course and is well 1 year after his operation. Establishing a diagnosis of extranodal lymphoma can be difficult, especially in HIV-positive or AIDS patients. Thus, performing a laparotomy is justified to confirm a diagnosis and decide upon the most appropriate treatment. However, in about 10% of these patients, only surgical resection allows for the diagnosis. In accordance with other reports, our experience confirms that, in contrast with AIDS patients, HIV-positive patients have a similar prognosis as non-HIV patients, and are suitable candidates for even major surgical procedures.