The Immunohistochemical Patterns of the beta-Catenin Expression in Pilomatricoma

Pilomatricoma is a benign follicular tumor that is composed of basaloid cells, transitional cells and shadow cells. beta-Catenin is a 92-kDa protein, and it plays important roles in cell-cell adhesion at the cell membrane and signal transduction in the nucleus. beta-Catenin has recently been shown to play an important role in the formation of hair follicle-related tumors, including pilomatricoma. However, the pattern and the intracellular localization of the beta-Catenin expression are still controversial.

We wanted to evaluate the pattern and the intracellular localization of the beta-Catenin expression in pilomatricoma by performing immunohistochemical staining.

Twenty-seven paraffin-embedded tissue samples that were diagnosed as pilomatricoma were immunohistochemically stained with beta-Catenin antibody.

Basaloid cells were found 15 samples of the total 27 pilomatricomas. All (15/15) of the basaloid cells strongly expressed beta-Catenin, but the transitional cells and the shadow cells did not. In the basaloid cells, the nuclei and membranes showed prominent beta-Catenin immunoreactivities, but the cytoplasm showed weak beta-Catenin immunoreactivity.

This study confirmed that the nucleus and membrane of all the basaloid cells in the pilomatricomas showed a strong beta-Catenin expression, but the transitional cells and shadow cells showed negative beta-Catenin immunoreactivity.