Trichofolliculoma: A Case Series

Abstract

Trichofolliculoma (TF) is a rare benign adnexal follicular tumor, described as hamartoma with follicular differentiation according to some authors. It typically appears during adulthood on the face or scalp as an isolated nodule with protrusion of central tufted hairs. We present a retrospective series of eleven patients with histologically confirmed TF to evaluate epidemiological, clinical, and histopathologic characteristics. The mean age at excision was 46 years with extremes ranging from 20 to 75 years. The sex ratio M/F was 0.37. Clinical presentation was a papule or nodule with an average diameter of 6,7mm (2-15 mm), firm with central pit in 54 percent and visible emerging vellus hairs in 18 percent of cases only. The localization was on the face in seven cases (63.6%) and only four cases were located outside the face (scalp [n=2], sub mammary fold [n=1] and shoulder [n=1]). Histologically, a cystically dilated hair follicle containing keratinous material with several mature and immature branched follicular structures is described in all cases. According to our series, TF occurs predominantly in women without age predilection, in the face. Central tufted hairs are only found in a minority of cases corresponding histologically to many secondary vellus hair follicles. In fact, histopathological examination is the gold standard for the diagnosis because clinical diagnosis could be challenging. Histology and dermoscopy may vary according to the age of the lesion. To date, only few case series have been published.

Keywords: Trichofolliculoma; adnexal tumor; dermatoscopy.

FIGURE 1.

A) pigmented umbilicated well-defined nodule measuring 1cm on the sub mammary fold; B) Two pink nodules with central pit and emerging white vellus hairs on the cheek

FIGURE 2.

A) Clinical appearance: Two flesh colored to pink well-defined papules measuring 3mm on the nose; B) Dermoscopic examination: well-defined, yellow structureless area without noticeable vessels

FIGURE 3.

A) Histopathological image showing a cystically dilated follicle (star) with numerous follicles varying in maturity arising from the lateral wall (arrow) (HE*25); B) On higher magnification, the secondary follicles can be better appreciated (HE*100).