title: Melanoma arising from a long-standing pigmented trichoblastoma: clinicopathologic study with complementary aCGH/mutational analysis.
abstract: Trichoblastoma is a benign cutaneous adnexal tumor, composed mostly of follicular germinative cells. Its pigmented variant is colonized by numerous dendritic melanocytes. So far, only one case in the literature describes a combination of trichoblastoma and melanoma. We report the case of a 62-year-old man who had a slow-growing mass of the left flank present since childhood. This 8-cm mass was surgically removed when it became ulcerated and associated with axillary lymph nodes. Histologically, this tumor was strictly dermal and composed of 2 intermingled components. Large sheets of atypical, proliferating epithelioid cells predominated. Dispersed solid nests or cribriform epithelial islets encased in fibrous tissue were also seen. Some nests displayed a massive colonization by pigmented dendritic melanocytes. On immunohistochemical staining, the sheets of atypical cells expressed focally but strongly S100 protein, MelanA, HMB45, and MiTF. Epithelial structures diffusely expressed pancytokeratin AE1/AE3, KL1, and pleckstrin homology-like domain, family A, member 1. Based on these results, we diagnosed an intradermal melanoma, possibly developed from dendritic melanocytes colonizing a giant pigmented trichoblastoma. Direct sequencing of the melanoma revealed a rarely described NRAS mutation c.34G>T (G12C). Array comparative genomic hybridization displayed a complex profile somewhat divergent from standard melanoma profiles. The patient died of widespread metastatic disease 8 months after initial diagnosis.
authors: *Département de Biopathologie, Centre Léon Bérard, Lyon, France; †Cancer Diagnosis and Pathology Group, Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, Australia; ‡Northern Translational Cancer Research Unit, Sydney Medical School, University of Sydney, Sydney, Australia; §Laboratoire de Pathologie, St Savine, France; ¶Services de Dermatologie, and ‖Pathologie, Institut Gustave Roussy, Villejuif, France; and **Service de Dermatologie, Hôpitaux de Strasbourg, Strasbourg, France.
authors: Gilles
authors: G
authors: Benaïm
authors: Christine
authors: C
authors: Castillo
authors: Michelle
authors: M
authors: Houang
authors: Lydia
authors: L
authors: Dejardin
authors: Christine
authors: C
authors: Mateus
authors: Qing
authors: Q
authors: Wang
authors: Daniel
authors: D
authors: Pissaloux
authors: Gorana
authors: G
authors: Tomasic
authors: Bernard
authors: B
authors: Cribier
authors: Arnaud
authors: A
authors: de la Fouchardière
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics*; D001706:Biopsy; D055028:Comparative Genomic Hybridization; D004252:DNA Mutational Analysis; D017809:Fatal Outcome; D020558:GTP Phosphohydrolases / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008543:Melanins / Q000032:analysis; D008544:Melanocytes / Q000737:chemistry / Q000473:pathology; D008545:Melanoma / Q000737:chemistry / Q000235:genetics* / Q000556:secondary; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D018294:Neoplasms, Adnexal and Skin Appendage / Q000737:chemistry / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D012878:Skin Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D013997:Time Factors
chemical_list: D014408:Biomarkers, Tumor; D008543:Melanins; D008565:Membrane Proteins; D020558:GTP Phosphohydrolases; C579846:NRAS protein, human