Surgical treatment of primary neuroendocrine tumors of the liver.

Primary neuroendocrine tumor (NET) of the liver is a very rare neoplasm, requiring strict exclusion of possible extrahepatic primary sites for its diagnosis. We have analyzed our clinical experience of eight patients with hepatic primary NET. From January 1997 to December 2006, eight patients with a mean age of 50.4 +/- 9.5 years underwent liver resection for primary hepatic NET. Seven patients underwent preoperative liver biopsies, which correctly diagnosed NET in four. Of the eight patients, six underwent R0 and two underwent R1 resection. Diagnosis of hepatic primary NET was confirmed immunohistochemically and by the absence of extrahepatic primary sites. All tumors were single lesions, of mean size 8.6 +/- 5.7 cm, and all showed positive staining for synaptophysin and chromogranin. During a mean follow-up of 34.0 +/- 39.7 months, three patients died of multiple liver metastases after tumor recurrence, whereas the other five remain alive to date, making the 5-year recurrence rate 40% and the 5-year survival rate 56.3%. Univariate analysis showed that Ki67 proliferative index was a risk factor for tumor recurrence. In conclusion, although primary hepatic NET is very rare, it should be distinguished from other liver neoplasms. The mainstay of treatment is curative liver resection.