title: Pigmented desmoplastic trichilemmoma.
abstract: Desmoplastic trichilemmoma (DT), the pseudomalignant variant of conventional trichilemmoma described by Hunt et al in 1990, displays a superficial lobular growth pattern of glycogen-rich cells with peripheral nuclear palisading surrounded by a thickened basement membrane. DT differs from its conventional counterpart by showing a central hyalinized area with epithelial cords and strands mimicking invasive carcinoma. We report a case that fully satisfies the criteria for DT and, in addition, shows an extensive melanocytic cell component and prominent melanin deposition. To our knowledge, a pigmented variant of DT has not been reported and should be recognized in order to appropriately face the differential diagnosis with malignant pigmented tumors particularly pigmented basal cell carcinoma (BCC).
authors.affiliation: Department of pathology, Hospital Clínico Universitario, University of Valencia, Valencia, Spain.
authors.forename: Carolina
authors.initials: C
authors.lastname: Martínez-Ciarpaglini
authors.affiliation: Department of pathology, Hospital Clínico Universitario, University of Valencia, Valencia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Monteagudo
keywords: desmoplastic trichilemmoma; outer root sheath; pigmented skin tumors