NEUROENDOCRINE DIFFERENTIATION IN THYMIC EPITHELIAL TUMORS WITH SPECIAL REFERENCE TO THYMIC CARCINOMA AND ATYPICAL THYMOMA

Citation
T. Hishima et al., NEUROENDOCRINE DIFFERENTIATION IN THYMIC EPITHELIAL TUMORS WITH SPECIAL REFERENCE TO THYMIC CARCINOMA AND ATYPICAL THYMOMA, Human pathology, 29(4), 1998, pp. 330-338
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Pathology
Journal title
ISSN journal
0046-8177
Volume
29
Issue
4
Year of publication
1998
Pages
330 - 338
Database
ISI
SICI code
0046-8177(1998)29:4<330:NDITET>2.0.ZU;2-0
Abstract
To determine the neuroendocrine (NE) features of thymic epithelial tum or, immunohistochemistry and electron microscopy studies were performe d on eight NE tumors (thymic carcinoids) and 26 non-NE tumors (nine th ymic carcinomas, five atypical thymomas, and 12 thymomas other than ly mphocytic thymoma). Immunohistochemical studies were performed with an tibodies against general markers for NE cells (synaptophysin, alpha su bunit of a guanine nucleotide-binding protein, Go, and small-cell lung carcinoma cluster 1 antigen), and a broad panel of antibodies for hor monal substances. Thymic carcinoid showed synchronous diffuse immunore activity for the three NE markers and contained cells that were positi ve for a variety of hormonal products: human chorionic gonadotropin (h CG) alpha-subunit (eight of eight), hCG beta-subunit (three of eight), adrenocorticotropic hormone (ACTH) (three of eight), calcitonin (two of eight), calcitonin gene-related peptide (two of eight), and seroton in tone of eight). Conversely, although positivity for NE markers was neither synchronous nor diffuse in non-NE tumors, seven of nine thymic carcinomas, three of five atypical thymomas (focal or dispersed distr ibution), and none of the five thymomas were positive for at least two of these NE markers. A small number of neoplastic cells were positive for hCG alpha-subunit or ACTH in three thymic carcinomas and one atyp ical thymoma. Ultrastructurally, dense core granules (DCG) were much m ore frequent in thymic carcinoid, but several DCG-like granules were i dentified in 12 of 13 non-NE tumors with or without immunoexpression o f NE markers. The presence of focal or dispersed NE cells in thymic ca rcinoma and atypical thymoma may reflect multidirectional differentiat ion within the tumor, which, like cytological atypia, epithelial CD5 e xpression, and lack of immature T cell infiltration, may be another fe ature of this group at thymic tumors. Copyright (C) 1998 by W.B. Saund ers Company.