Primary cystic neuroendocrine tumor of the liver: case report

85% of neuroendocrine tumors (NET) originate in the gastrointestinal tract, which is why their primary hepatic location is very rare; NETs most frequently cause metastases to the liver; so when diagnosed, a hepatic NET is considered initially metastatic. Diagnosis of primary hepatic neuroendocrine tumors (PHNET) should be performed by excluding extrahepatic NETs and through histological confirmation. The objective of this article is to present a case of PHNET.

75-year-old male patient, who presented asthenia, adynamia, abdominal pain in the right hypochondrium, six-month weight loss, with a right subcostal palpable tumor. Imaging studies reported a lesion in the right hepatic lobe, multilobulated, heterogeneous, with poorly defined margins and with cystic areas. It was performed diagnostic laparotomy and then a hepatic tumorectomy, whose product measured 16.0 x 10.0 x 6.5 cm, with two cystic cavities of 13.2 and 11.5 cm of hematic content. Microscopically, cells with neuroendocrine differentiation, with positive immunoreactivity to chromogranin were observed. It was diagnosed well-differentiated neuroendocrine neoplasm, with cystic degeneration.

Even though it is excluded a NET from an extrahepatic primary site, the tumor etiology of an important proportion of patients with PHNET will be due to an unknown primary tumor that will become apparent over time; hence, the need to follow up as long as possible.