Desmoplastic trichilemmoma: a rare tumor of the eyelid

Desmoplastic trichilemmoma of the scalp: case report and literature review of immunohistochemical staining features

Desmoplastic trichilemmoma (DT) of the scalp is a rare disease. In this report, we describe a 67-year-old man who had a small papule lesion around the hairline of the left scalp for more than 40 years. The lesion had rapidly grown to become a solitary, round, 15-mm neoplasm within 6 months. Histopathological examination showed that the mass was composed of a peripheral layer of columnar cells with nuclear palisading resembling the outer root sheath; the mass was surrounded by a thickened glassy basement membrane. The stroma in the center of the mass displayed solid, hyaline degeneration and an eosinophilic pattern, streaked with epithelial cords or islands. Immunohistochemical evaluation showed diastase-resistant, periodic acid–Schiff-positive desmoplastic stroma at the center, and Ber-EP4-negative tumor cells (CD34-positive focally and Bcl-2-positive at the periphery). The tumor was completely resected, and no recurrence occurred during the follow-up period. In this report, we also summarize immunohistochemical features from previous reports of DT, facilitating differential diagnosis of DT from some invasive skin tumors.

A Hyalinized Trichilemmoma of the Eyelid in a Teenager

A 16-year-old African American male, the youngest patient to date, presented with a well-circumscribed upper eyelid lesion. On excision, the dermal nodule was contiguous with the epidermis, displayed trichohyalin-like bodies in an expanded outer root sheath, and was composed chiefly of small cellular clusters separated by a prominent network of periodic acid Schiff -positive hyaline bands of basement membrane material. The tumor cells were positive for high molecular weight cytokeratins (CK) 5/6, CK14, and CK34βE12 and were negative for CK7, carcinoembryonic antigen and epithelial membrane antigen. Negative S100, glial fibrillary acidic protein, and smooth muscle actin immunoreactions ruled out a myoepithelial lesion. The Ki-67 proliferation index was <10%. The diagnosis was a hyalinized trichilemmoma, contrasting with the more common lobular type. As an isolated lesion, trichilemmoma does not portend Cowden syndrome.

Eyelid desmoplastic trichilemmoma: 2 case reports and review

Desmoplastic trichilemmomas (DTs) are a rare variant of trichilemmomas first described in 1985. Since then, 11 cases involving the eyelid have been reported. Two cases of this study raise this total to 13. DTs are often clinically confused with basal cell carcinoma and must be proven by biopsy to obtain the correct diagnosis. These lesions are more commonly present in patients older than 50 years. Despite the fact that they are benign, they are often associated with basal cell carcinomas and as such should be managed carefully, requiring excisional biopsy with frozen borders or Mohs controlled margins.