Background
Trichofolliculoma represents an uncommon hamartoma of hair follicle tissue, typically occurring on the face of adults. [1]
The prognosis is excellent, and therapy is usually directed toward cosmetic improvement.
Pathophysiology
Although the precise etiology of trichofolliculoma is uncertain, these tumors are not associated with systemic disease or other skin disorders. Trichofolliculomas are believed to represent abortive differentiation of pluripotent skin cells toward hair follicles.
Epidemiology
Frequency
Trichofolliculoma represents an uncommon clinical entity.
Race
In reported cases, trichofolliculomas demonstrate no definitive racial predilection.
Sex
No definitive sexual predilection is observed in reported cases, although sporadic reports indicate a probable male preponderance. [2]
Age
From published reports, trichofolliculoma appears to primarily be a tumor of adults; however, at least 1 case of congenital trichofolliculoma has been reported. [3]
Prognosis
The prognosis is excellent. Although reports exist of recurrence at the primary site, these events are rare. Trichofolliculomas are associated with minimal clinical morbidity; no confirmed cases of malignant transformation or clinical mortality are reported in the literature.
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Low-power view of trichofolliculoma with a primary follicle opening onto the skin surface.
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Edge of the primary follicle with associated secondary and tertiary budding follicular structures.
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Higher magnification of budding follicular structures.
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Low-power view of a section of trichofolliculoma demonstrating budding follicular structures and associated stroma.
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Higher magnification of budding follicular structures and associated stroma.
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Low-power view of sebaceous trichofolliculoma demonstrating dilated, primary follicle; budding follicular structures; and numerous associated sebaceous lobules.
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Higher magnification of central primary follicle and associated sebaceous lobules.
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Clinical appearance of trichofolliculoma.
