Primary Pseudocystic Hepatic Neuroendocrine Tumor: A Case Report and a Case for Changing Preoperative Evaluation

Introduction: Neuroendocrine tumors(NET) represent rare neoplasms with majority primary NETs being gastroenteropancreatic or bronchopulmonary origin. A hepatic NET is most likely a metastastic lesion. Cystic hepatic lesions are commonly either infectious, benign cystic lesions, or if malignant; a cystadenocarcinoma, hepatocellular carcinoma, or metastasis with cystic degeneration. Primary hepatic neuroendocrine tumors(PHNETs) and primary pseudocystic hepatic neuroendocrine neoplasms are exceedingly rare. Standard tumor markers, AFP and CEA, are almost invariably normal. Pre-operative neuroendocrine markers for solitary liver masses may prove beneficial. Methods: We present a case of a 57-year old healthy female with a finding of a large multi-lobulated cystic right hepatic lesion, diagnosed histopathologically as a pseudocystic primary neuroendocrine tumor. Case Presentation (Results): A 57-year old healthy female had a large hepatic cystic mass on ultrasound. An abdominal MRI showed a large, cystic, multi-lobulated, right hepatic lesion with internal septations. The mass grossly appeared to represent a biliary cystadenoma. Histopathologically, staining was positive for markers consistent with neuroendocrine origin, diagnostic of primary pseudocystic neuroendocrine tumor. Discussion: NETs have a rare, but increasing incidence. When a hepatic neuroendocrine tumor is identified, the diagnosis usually represents metastasis. PHNET is extremely rare. PHNETs are difficult to diagnose pre-operatively. Tumor markers AFP, CEA, and Ca 19-9 are almost uniformly normal. As there has been a trend toward increasing incidence of NETs, this suggests an increasing trend in PHNET cases. Here, we present a case of pseudocystic PHNET diagnosed in a 57-year old female. Our case supports consideration for obtaining pre-operative CgA for all hepatic lesions.