Utility of Immunohistochemical Analysis of CD34 expression in the Diagnosis of Lesions with trichilemmal Differentiation

A 54-year-old patient was seen for a tumor on the upper lip present for 4 months and clinically compatible with a basal cell carcinoma (Figure 1A). This was surgically removed. Histopathology revealed a clearly defined tumor proliferation composed of lobed formations of cells with clear cytoplasm presenting the typical peripheral palisading of trichilemmoma (Figure 1B). The periphery contained an area of desmoplasia, with small epithelial cells forming chords and nests, immersed in hyalinized collagen (Figures 1B y 1C). The cell membranes were CD34-positive (Figure 1D) and the lesion was diagnosed as trichilemmoma with desmoplastic areas.