Abstract
Objectives
Neuroendocrine neoplasms (NENs) are divided into two major categories according to the 2018 WHO expert consensus proposal: well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinoma (NECs). Primary liver NENs are very rare and majority of NENs in the liver are metastatic. In this study, we retrospectively reviewed NENs in the liver diagnosed by fine-needle aspiration biopsy (FNAB).
Methods
We retrospectively reviewed malignant neoplasms diagnosed by imaging-guided liver FNAB performed between 2010 and 2018 in our institution. Patients’ electronic medical records and selective slides were reviewed.
Results
A total of 624 liver FNAB cases with a diagnosis of positive for malignancy were identified. Among those cases, 56 cases (9%) were NENs. Poorly differentiated NECs constituted 71% (40/56) of cases, and well-differentiated NETs constituted 29% (16/56) of cases. The most common primary sites of poorly differentiated NECs were lung (35%, 13/40), followed by pancreas (20%, 8/40), GI tract (17.5%, 7/40), GU (7.5%, 3/40), breast (5%, 2/40), head and neck (2.5%, 1/40), GYN tract (2.5%, 1/40), and CNS (dedifferentiated glioblastoma, 2.5%, 1/40). The remaining three cases (7.5%, 3/40) were diagnosed as primary liver NECs based on the clinical presentation. All three patients presented with a single large liver mass with no other mass lesions identified in other organ systems. For well-differentiated NETs, majority were from the GI tract (81.3%, 13/16), followed by pancreas (6.25%, 1/16) and lung (6.25%, 1/16). One patient was diagnosed with metastatic NET of unknown primary.
Conclusion
NENs in liver are predominantly metastatic, and majority of them are high-grade NECs. Most of well-differentiated NETs are metastases from the GI tract, while more than one-third of poorly differentiated NECs are metastases from the lung. Primary liver NENs also occur and all three cases in this study are poorly differentiated NECs.
PAX8 is expressed in pancreatic well-differentiated neuroendocrine tumors and in extrapancreatic poorly differentiated neuroendocrine carcinomas in fine-needle aspiration biopsy specimens
