Excerpt from Folliculoma

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Background

Folliculoma, also known as trichofolliculoma, is an asymptomatic, rare, benign tumor of the hair follicle, which is a hamartoma. Clinically, it appears as a small, solitary, skin-colored nodule on the face or scalp in adults. Often, a tuft of wool-like hair protrudes from a central pore.

Pathophysiology

Trichofolliculomas represent a hamartomatous, or organoid, adnexal tumor originating from the hair follicle. Immunohistochemical studies with cytokeratins reveal folliculomas differentiate mainly toward the hair bulge and the outer root sheath in the isthmus. All stages of follicular development can be observed in the lesion; the tumor is benign.

Frequency

United States

Folliculomas are uncommon. Given its benign nature, no large screening for this hair follicle tumor has been performed in the general population; therefore, an exact incidence has not been determined.

International

The condition has been reported worldwide. It is a rare entity with all nationalities.

Mortality/Morbidity

Folliculomas are benign asymptomatic lesions that may present as a cosmetic problem. Clinically, they are more likely to be confused with a more serious entity, ie, basal cell carcinoma; however, they have no malignant potential.

Race

A study performed with military personnel demonstrated that folliculomas are more common in whites than in any other race.

Sex

Folliculomas occur predominantly in males.

Age

• Although folliculomas represent a maldevelopment of the hair follicle unit, the lesions do not usually manifest until the late teens or possibly until the fourth decade of life. However, one report describes a congenital folliculoma on the cheek.

Please click here to view the full topic text: Folliculoma