Asymptomatic glucagonoma presenting with an isolated hepatic nodule

A 37-year-old male patient, without any particular symptoms apart from moderate right upper quadrant postprandial pain, was found to have a liver mass identified as a glucagon-producing tumor. Plasma glucagon levels were slightly increased, whereas those of other gut peptides were within the normal range. Despite an extensive pre- and intraoperative diagnostic work-up, a presumed primary glucagonoma remained undetected. This unusual presentation with the absence of any symptoms typical of glucagonoma, as well as the presence of histopathological features characteristic of both benign and malignant forms of glucagonoma, make this case very peculiar. A clinically silent, apparently unrelated adenocarcinoma of the left colon was also found. The concomitant presence of a glucagonoma and a carcinoma of the large intestine has not been previously reported, and its significance remains unclear.