Pilomatricomal Horn

Abstract

We describe a pilomatricomal horn on the right arm of a 39-year-old man. Although initially the tumor was clinically thought to be a verruca vulgaris, the microscopic features were similar to those found in classic pilomatricoma, except for the epidermal location and the presence of a cutaneous horn. Light microscopy showed replacement of the epidermis by basaloid cells, with masses of cornified material containing shadow cells that formed a cutaneous horn. Whereas classic pilomatricoma is confined to the deep reticular dermis or subcutis, the present case represents a unique heretofore unreported epidermal variant of pilomatricoma that pathologists should be aware of to differentiate it from malignant epidermal tumors.

Giant Pilomatrical Tumor With Broad Epidermal Components: An Example of Histological Diversity and a Potential Diagnostic Pitfall of Tumors With Pilomatrical Differentiation

“…Alternatively, the tumor might have partly arose in the epidermis, similar to the previously described superficial pilomatricoma variant. 13,14 Overall, our case extends the range of the histological variations reported in pilomatrical tumors. We believe that this unusual phenomenon should be recognized so as to prevent misdiagnosis, including other cutaneous malignancies exhibiting pilomatrical differentiation.…”

Lentigo Malignant Melanoma Presenting with Cutaneous Horn

“…Although there are some cutaneous horn reports associated with BCC, SCC, sebaceous carcinoma, pilomatricoma, and trichilemmal carcinoma in the literature, 9–13 we found only one case report associated with melanoma. Cristobal and colleagues 3 published the first case report defined as verrucous malignant melanoma arising as a cutaneous horn.…”

SkIndia Quiz 9: Solitary cystic nodule with a horn on the thigh of elderly male

“…A case of superficial pilomatricoma arising within epidermis and presenting with a horn (pilomatricomal horn) is reported. [8] In our case, no connection of overlying horn with cyst was found.…”