[Plaque variant of trichoblastic fibroma]

Tricoblastic fibroma is a rare benign skin tumor originating in the hair follicle. There are two clinical presentations: nodular and plaque variants. The plaque variant is almost exclusively located on the face with deep tissue infiltration.

A 38-year-old man presented with a 2 cm diameter cutaneous plaque located on the right cheek. It had first been noted by the patient 3 years earlier and had enlarged slowly. On examination, the plaque was well defined, yellowish and slightly indurated. The first clinical diagnosis was basal cell carcinoma and the plaque was removed. Histology provided the diagnosis of trichoblastic fibroma. The patient remains well, with no evidence of recurrence, 10 months after excision.

Trichoblastoma is an inclusive term for all benign cutaneous neoplasms that are mostly composed of follicular germinative cells. According to Altman, the plaque variant of trichoblastic fibroma is a poorly circumscribed neoplasm, particularly at its lateral and deep margins. This author also states that mitotic figures are more numerous in the plaque variant of trichoblastic fibroma and considers this clinical variant as a low-grade follicular malignancy.