Basaloid follicular hamartoma: three cases with localized and systematized unilateral lesions

Two patients having a localized plaque of alopecia on the scalp, and one with a systematized unilateral epithelial nevus exhibited a histologically distinctive form of follicular hamartoma. In the affected areas individual hair follicles were replaced, or were associated with solid strands and branching cords of undifferentiated basaloid cells, filled in between by fibrous stroma resembling either a miniature premalignant fibroepithelial tumor of Pinkus, a small trichoepithelioma, or a basal cell epithelioma. The relation between these 3 patients and cases reported as linear unilateral basal cell nevus with comedones and generalized hair follicle hamartoma associated with myasthenia gravis is discussed.