title: Collision of squamous-cell carcinoma with melanoma in situ in a child with xeroderma pigmentosum.
abstract: Coexistence (collision) of two different neoplasms in the same lesion has previously been documented by several authors. In this report, we describe a 13-year-old boy with xeroderma pigmentosum presenting with squamous-cell carcinoma and melanoma arising at the same site on the nose. Histopathologically, the melanoma component of the lesion was located mainly eccentrically to the squamous-cell carcinoma component. Immunohistochemical stains confirmed the histopathologic findings. Mutations for p53 assessed using single-strand conformation polymorphism, and sequencing analysis revealed a CC-to-TT transition at codon 159 of the p53 gene in the squamous-cell component but not in the melanoma component. This finding suggests a possible role for UV in the pathogenesis of at least the squamous-cell component of the tumor. To the best of our knowledge, this is the first report of a collision tumor comprising squamous-cell carcinoma and melanoma arising in childhood.
authors.affiliation: Department of Dermatology, Karl Franzens University, Graz, Austria. angelika.hofer@kfunigraz.ac.at
authors.forename: A
authors.initials: A
authors.lastname: Hofer
authors.forename: S
authors.initials: S
authors.lastname: Kaddu
authors.forename: H
authors.initials: H
authors.lastname: Seidl
authors.forename: H
authors.initials: H
authors.lastname: Kerl
authors.forename: P
authors.initials: P
authors.lastname: Wolf
mesh_terms: D000293:Adolescent; D002294:Carcinoma, Squamous Cell / Q000150:complications* / Q000473:pathology; D006801:Humans; D008297:Male; D008545:Melanoma / Q000150:complications* / Q000473:pathology; D009378:Neoplasms, Multiple Primary / Q000473:pathology; D009669:Nose Neoplasms / Q000150:complications* / Q000473:pathology; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology; D014983:Xeroderma Pigmentosum / Q000150:complications* / Q000473:pathology