[Large Primary Hepatic Neuroendocrine Tumor with Right Trisectionectomy-A Case Report].

A large mass in the liver was incidentally observed on abdominal ultrasonography of a 75‒year‒old female during health surveillance. Computed tomography (CT) and magnetic resonance imaging revealed a tumor (φ>12 cm) in the medial segment of the liver. A liver biopsy was performed, and the tumor was histopathologically diagnosed as a neuroendocrine tumor (NET) G1. 18F‒fluorodeoxyglucose positron emission tomography‒CT (PET‒CT) and somatostatin receptor scintigraphy (SRS) revealed concomitant uptake in the hepatic tumor and no abnormal uptake in other organs; thus, the tumor was diagnosed as a primary hepatic NET (PHNET). Radical resection required right trisectionectomy of the liver, with little future remnant liver volume. The radical resection was performed 3 weeks post portal embolization. There were no surgical complications or obvious recurrence for 1 year post‒surgery. PHNETs are extremely rare and are difficult to diagnose using routine imaging modalities. PET‒CT and SRS are useful to exclude the presence of extrahepatic lesions and histopathological examination is required to diagnose PHNETs. Surgical resection is the first‒line treatment for PHNETs and even if the PHNET is large, a favorable prognosis can be achieved with radical resection.