Long-term postresection prognosis of primary neuroendocrine tumors of the liver.

Purpose: Primary hepatic neuroendocrine tumor (PHNET) is a very rare neoplasm, requiring strict exclusion of metastasis from possible extrahepatic primary sites for its diagnosis.

Methods: We reviewed our clinical experience of 13 patients with primary hepatic NET who underwent liver resection from January 1997 to December 2015.

Results: The mean age of the 13 patients (8 males and 5 females) was 51.1 ± 12.8 years; the most common clinical manifestation was vague, nonspecific abdominal pain (n = 9). Of them, 11 patients underwent preoperative liver biopsy, 7 of which correctly diagnosed as neuroendocrine tumor (NET). Ten patients underwent R0 resection, and 3 underwent R1 resection. Diagnosis of PHNET was confirmed both immunohistochemically and by absence of extrahepatic primary sites. All tumors were single lesions, with a mean size of 9.6 ± 7.6 cm and a median size of 4.3 cm; all showed positive staining for synaptophysin and chromogranin. During a mean follow-up period of 95.1 ± 86.6 months, 7 patients died from tumor recurrence, whereas the other 6 remain alive to date, making the 5-year tumor recurrence rate 56.0% and the 5-year patient survival rate 61.5%. When confined to R0 resection, 5-year recurrence and survival rates were 42.9% and 70.0%, respectively. Univariate analysis showed that Ki-67 proliferative index was the only risk factor for tumor recurrence.

Conclusion: PHNET is a very rare tumor with no specific clinical features, and its final diagnosis depends primarily on pathology, immunohistochemistry, and exclusion of metastasis from other sites. Aggressive surgical treatment is highly recommended for PHNET because of acceptably favorable postresection outcomes.