Primary hepatic endocrinomas (carcinoids and variant neoplasms). A statistical evaluation of 126 reported cases

This study was undertaken to evaluate the statistical results of a large collected series of primary hepatic endocrinomas including carcinoids from extensive clinicopathologic aspect, and to provide the information to investigators engaged in this particular field of research. Primary hepatic endocrinomas variously termed as endocrine cell carcinoma (ECC), neuroendocrine carcinoma (NEC), carcinoid, and other carcinomas with endocrine components (CECs), have been rarely reported in literature. A total of 126 reported cases were registered in the Niigata Registry for gut-pancreatic endocrinomas. They consisted of a carcinoid group with typical carcinoids (n=82) and atypical carcinoids (n=19) and another group with other variant endocrinomas, briefly expressed as the variant group (n=25) in this study. The number of females was larger than that of males in the carcinoid group (M/F=0.58) and reversely males were predominant in the variant group (M/F=1.78). The average age was considerably older in the carcinoid group as compared to that in the variant group (53.9 years vs 48.3 years). The carcinoid group (either typical, atypical or both) showed a significant lower value than the variant group in metastasis rates in the large (over 50 mm) tumor series (43.3% vs 75.0%: P<0.05), and higher than the latter in serotonin positivity demonstrated by immunohistochemistry (37.0% vs 11.1%). While no significant difference was present between the two groups, cases with large tumors over 50 mm were found at a high rate (P<0.01) in approximately three fourths of each group, i.e. 76 out of a total of 100 cases recorded, and the liver was more often involved by metastasis than lymph nodes in the carcinoid group (32.7% vs 19.8%: P<0.05) though no significant difference was noted between these two sites in the variant group. The five-year survival rates calculated by the Kaplan-Meier method showed better results in the carcinoid group than in the variant group but with no statistically significant difference (92.4% vs 68.1%). A close similarity found in many aspects of the two groups suggested endocrinomas in the present study apparently belong to one family of CECs or briefly "carcinoid family". Regarding the more detailed statistical analyses, further accumulation of well-documented cases is needed.