Publication Date:
2013-09-08
Description:
Aims Morphologic complexity hampers histologic classification of thymomas. The use of novel differentiation and maturation markers of cortical and medullary thymic epithelial cells (cTEC, mTEC) might provide an approach to understand the underlying biology of these tumours. Methods and Results 57 thymomas were studied by immunohistochemistry. Cortical markers used were β5T, PRSS16 and cathepsin V. Medullary markers used were CD40, Claudin-4, AIRE and desmin. Involucrin and cytokeratin 10 were used to study terminal mTEC maturation. Irrespective of histological subtype, most thymomas contained distinct areas with cortical and medullary differentiation. Type B1, B2 and AB thymomas showed marked bi-lineage differentiation with lack of terminal mTEC maturation in type AB. Type AB thymomas were unique by showing areas where cells with either cortical or medullary differentiation were intimately “mixed” at the single cell level. Type B3 and A thymomas showed only abortive lineage differentiation and maturation. Conclusions Thymomas exhibit highly characteristic patterns of bi-lineage TEC differentiation that reflect the histological subtypes recognized by the WHO classification. We hypothesize that thymomas arise from a thymic precursor cell with different cortical and/or medullary maturation defects. This article is protected by copyright. All rights reserved.
Print ISSN:
0309-0167
Electronic ISSN:
1365-2559
Topics:
Medicine
