Within the central cystic structure (comedo), a hair shaft and keratin flakes are seen. The lining of the central follicle often has a prominent granular layer.

Smaller secondary hair follicles, some of which have well-developed sebacecous glands (left center), radiate from the central follicle. The caput medusa-like architecture of this hamartomatous lesion is best seen on low power.

Trichofolliculoma is considered a hamartoma of hair follicle components. They are benign and typically occurring on the face of adults. The typical clinical appearance is that of a flesh-colored or whitish nodule on the face (Fletcher, Howard).

Histologically, there is central cystically-dilated follicle filled with keratin flakes ("comedo"). From this central cavity, there are numerous secondary hair follicles with vellus hairs that bud off, creating a "caput medusa" appearance. The central cystic follicle is usually connected to the epidermis. A rare variant of trichofolliculoma is a sebaceous trichofolliculoma in which there are well-developed sebaceous glands surrounding the central comedo cavity (Rapini, Alsaad).

Simple excision (done for cosmetic reasons) is curative.