Facial cutaneous horn in three different conditions: A highlight of a malignancy risk

Trichilemmal Horn: A Case Report

“…1 The CD34 antigen is a specific marker for external sheath of the hair follicle and tumors derived or differentiated for this type of epithelium are positive, as in the cases described as trichilemmal horn. 2,3 Some cases reported the appearance of trichilemal horn after rupture of trichilemal cysts, 3 which was not the case of our patient.…”

“…Lower limbs, followed by the head and back are the most affected regions. [1][2][3] As there is a higher prevalence in body extremities and cephalic region (photoexposed areas), the direct or indirect contribution of ultraviolet (UV) radiation to the disease pathogenesis in some patients has been discussed. 2 The diagnosis is made through macroscopic analysis and microscopic examination of the lesion, through excision and anatomopathological analysis.…”

“…2 The diagnosis is made through macroscopic analysis and microscopic examination of the lesion, through excision and anatomopathological analysis. 3 Possible differential histological diagnoses of the trichilemmal horn are hypertrophic actinic keratosis, keratoacanthoma, seborrheic keratosis, trichilemal cyst, trichilemoma and verruca vulgaris, 2 among others.…”

“…2 The prevalence is higher in women and in the age groups older than 50 years, with a predominance in extremities followed by the cephalic region. [1][2][3] Its etiopathogenesis remains uncertain, 3 however there are reports of its occurrence secondary to the rupture of a previous trichilemmal cyst. 3 The diagnosis is confirmed after excision and histopathological analysis, showing specific characteristics of this pathology.…”

“…[1][2][3] Its etiopathogenesis remains uncertain, 3 however there are reports of its occurrence secondary to the rupture of a previous trichilemmal cyst. 3 The diagnosis is confirmed after excision and histopathological analysis, showing specific characteristics of this pathology.…”