Liver Metastasis of Gastrointestinal Neuroendocrine Tumors: A Single Center Experience

BACKGROUND: Gastrointestinal neuroendocrine tumors (GI-NETs) are potentially malignant tumors, and their most common location of metastasis is the liver. OBJECTIVES: In this report, we will describe our experience with some clinical and pathologic findings of hepatic metastasis in a group of cases of GI-NETs at the largest referral center of GI and liver diseases in south Iran. MATERIALS AND METHODS: In this four-year study (2011 - 2014), all GI and liver NETs were extracted from the pathology files of hospitals affiliated with Shiraz University of Medical Sciences. After classification based on the world health organization guidelines, the patients were evaluated according to their location, sex, age, and proliferative index. After studying the imaging and clinical charts of liver-NET cases with an unknown primary location, a complete panel of immunohistochemical markers (TTF-1, CDX-2, CK-7, CK-2, etc.) was used to find the primary GI location. Carcinoid tumors from other sites, such as the lung, were omitted from this study. RESULTS: The most common primary site of metastatic GI-NET to the liver in our center was the small intestine, which was also the most frequent location of GI-NET without liver metastasis. No cases of appendiceal-NET were found with liver metastasis. In 8 cases (11.6%) with liver-NETs, no primary location was identified. GI-NETs with liver metastasis had a significantly higher grade and proliferative index compared with NETs without liver metastasis. CONCLUSIONS: Liver metastasis of neuroendocrine tumors in Iran presents in a very similar manner as that seen in western countries. In about 89% of cases with liver-NET, complete imaging, clinical, and pathological studies can help to identify the primary origin of the liver-NET, which is very important in the patient’s management.