Abstract

Trichoblastic fibroma is a benign trichogenic tumor that has both epithelial and mesenchymal components and exhibits partial follicular induction. We studied 4 cases of trichoblastic fibroma and reviewed their clinical and histologic features. Two tumors were present in the face. The remaining two were in the vulva and perianal area, respectively. The age of the patients ranged from 53 to 68 years, with an average age of 62. All were female. Histologically, the lesions showed a well circumscribed mass, located at dermo-subcutaneous junction in three patients and subcutaneous in one. They demonstrated mesenchymal induction evidenced by hair germ-like structure and perifollicular sheath. There was no connection between the tumor and epidermis. Differentiation toward hair structure led to the formation of the infundibulum through inner root sheath. Trichoblastic fibroma may be confused clinically and/or histologically with basal cell carcinoma. Identification of the mixed epithelial and mesenchymal components, and the absence of epidermal connection and cleft within the stroma are important in differentiating this benign neoplasm from basal cell carcinoma.

• Keywords: Trichoblastic fibroma