消化管カルチノイド―組織発生の面から

Histogenesis of Carcinoid Tumors

　カルチノイドの組織発生に関する問題は，広く腫瘍化の研究分野で癌の組織発生とも関連して興味深いと同時に重要な問題でもあるが，むしろこれからの課題で現状では定説はなく，いまだ仮説の段階と言える．この問題に関連し，解決の糸口になりそうな興味ある現象が文献上でも近年急速に増加している．これらの現象や著者らの経験をとりあげながら，この種の腫瘍群の組織発生の問題を2，3の方向から探ってみたいと思う．

　Some considerations on histogenesis of carcinoids are undertaken on the basis of our recent concept of the neoplasms of this particular category that carcinoids are a group of endocrine neoplasms originaing from the primordial cells of the endocrine or related cells of multiple sorts widely distributed in the organs and tissues of the primitive gut system.

　Morphologic variety reflected in the histologic classification, behavior to silver impregnations, occasionally encountered multisecretory function, atypical forms represented mainly by mixed type and by C type with concomitant mucus-secretion, coexistence of neoplastic cells of different types in a single neoplasm, and argyrophil cell microproliferations including microcarcinoids are all taken into consideration for the present discussion on histogenesis of carcinoids as the keys to possible solution of this problem.

　One of the hypotheses concerning the mechanism of neoplastic transformation of these neoplasms postulates that the neoplastic transformation may encounter with the preprimordial anlage cells in the Mphase in which these cells are capable of multidirectional differentiation and may result in multisecretory or mixed type carcinoids or in C type carcinoids with mucus-secretion including argentaffin cell adenocarcinoma (Soga) and goblet cell carcinoid of the appendix (Klein, Subbuswamy), and that it may as well act on the primordial anlage cells in the U-phase in which these cells are capable of unidirectional differentiation under the control of the field and may result in monosecretory or histologically uniform (A, B and some of C and D) type carcinoids. Thus, morphologic variety of carcinoids in histologic classification may well be considered to be a fairly faithful reflection of histogenetic variety of these neoplasms.

　It is, however, emphasized that the theoretical consideration on histogenesis of carcinoids should be more precisely established mainly on the basis of the testified phenomena supplemented by certain hypotheses only on inevitable occasions.