Mesenchymal–Epithelial Differentiation of Adamantinoma of Long Bones: An Immunohistochemical and Ultrastructural Study

Abstract

Three cases of adamantinoma were studied by electron microscopy and immunohistochemistry. In the tubular pattern, well-differentiated epithelial cells and glandular structures were present, in addition to ill-defined glands. In the basaloid pattern, less differentiated epithelial cells with discohesion were seen in the central epithelial masses. This study established the epithelial nature of some tubular structures with slit-like lumina, easily misinterpreted as capillaries by light microscopy. Results also showed that the irregular spaces observed within the basaloid pattern probably result from cell discohesion. Moreover, this investigation demonstrates the epithelial nature of a subset of spindle cells within the stroma of adamantinoma and offers ultrastructural evidence for a probable mesenchymal–epithelial transformation as its histogenesis.

Keywords::

• Adamantinoma
• electron microscopy
• mesenchymal–epithelial differentiation

ACKNOWLEDGEMENT

This work was partially presented at the Annual Meeting of the United States–Canadian Academy of Pathology, March 2007, San Diego, California.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.