Carcinoids of Gastrointestinal Tract: Significance of Differentiation andProliferation Markers

Overview

The group of 35 carcinoid tumours obtained from 34 patients was reviewed according to recenthistopathological criteria. Consequently, evaluation of the Grimelius staining and immunohistochemicaldetection of chromogranin A (CgA), Leu-7 (CD-57), synaptophysin, neuron-specific enolase(NSE), (
-III tubulin, Ki-67 and proliferating cell nuclear antigen (PCNA) was performed. Themajority of tumours (29, i.e. 83 %) were classified as typical carcinoids composed predominantly ofmixed solid and trabecular or solid and tubular growth patterns. Six tumours (17 %) revealedmore prominent cytological abnormalities corresponding with the diagnosis of atypical carcinoid.The majority of tumours (31, i. e. 93.9 %) showed granular cytoplasmic positivity in Grimeliusstaining and diffuse cytoplasmic positivity of NSE (34, i. e. 97.1 %). All of the 32 stained tumoursamples showed positive immunoreactivity for synaptophysin. A high percentage of tumours (32,i. e. 91.4 %) revealed also a positive reaction with antibody TU-20 detecting (
-III tubulin, a markerof an early stage of neuronal differentiation. Thirty-four tumours (97.1 %) showed granular cytoplasmicpositivity for both markers of neuroendocrine granules (CgA and Leu-7). One tumour(2.9 %) was positive only for Leu-7. Tumour cells revealed predominantly low proliferative activityevaluated by PCNA and Ki-67 immunodetection. Higher degree of proliferation was observedespecially in atypical carcinoids.

Key words:
gastrointestinal carcinoids – histology – immunohistochemistry – differentiation markers– proliferation