The Immunohistochemical Patterns of the β-Catenin Expression in Pilomatricoma

Background: Pilomatricoma is a benign follicular tumor that is composed of basaloid cells, transitional cells and shadow cells. β-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. β-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 βCatenin expression are still controversial. Objective: We wanted to evaluate the pattern and the intracellular localization of the β-Catenin expression in pilomatricoma by performing immunohistochemical staining. Methods: Twenty-seven paraffin-embedded tissue samples that were diagnosed as pilomatricoma were immunohistochemically stained with β-Catenin antibody. Results: Basaloid cells were found 15 samples of the total 27 pilomatricomas. All (15/15) of the basaloid cells strongly expressed β-Catenin, but the transitional cells and the shadow cells did not. In the basaloid cells, the nuclei and membranes showed prominent β-Catenin immunoreactivities, but the cytoplasm showed weak β-Catenin immunoreactivity. Conclusion: This study confirmed that the nucleus and membrane of all the basaloid cells in the pilomatricomas showed a strong β-Catenin expression, but the transitional cells and shadow cells showed negative β-Catenin immunoreactivity. (Ann Dermatol 22(3) 284∼289, 2010)