Trichilemmal keratosis. A clinicopathologic and immunohistochemical study of two cases.
Trichilemmal keratosis (TK) is an uncommon epidermal tumor that exhibits a keratinizing surface with the formation of a cutaneous horn and that clinically resembles a hyperkeratotic actinic keratosis. Histologically, there is verrucous hyperplasia of the epidermis with orthokeratotic hyperkeratosis. TK is characterized by abrupt keratinization without formation of a granular cell layer, in the same manner as that in which the outer root sheath keratinizes (trichilemmal keratinization). The epidermis is acanthotic and contains pale-staining keratinocytes. Epithelial lobules and small trichilemmal cysts are connected to the thickened epidermis. We describe the clinical, histologic, and immunohistochemical findings of two cases of TK.
Departments of Pathology, Hospital Universitario de Getafe, Madrid, Spain.
E
E
Poblet
J
J
Jimenez-Reyes
C
C
Gonzalez-Herrada
R
R
Granados
D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D005260:Female; D006197:Hair; D006801:Humans; D007642:Keratosis / Q000276:immunology / Q000473:pathology*
D018952:Antigens, CD34