title: Cutaneous Metastatic Melanoma Resembling a Halo Nevus, in the Setting of PD-1 Inhibition.
abstract: Malignant melanoma is a common source of cutaneous metastases and can occasionally adopt a histological appearance which mimics a primary melanocytic lesion, either benign or malignant. The authors describe a case of new cutaneous deposits of metastatic melanoma in a 70-year-old woman with a prominent admixed lymphocytic infiltrate, imparting a striking resemblance to a halo nevus. The authors believe this appearance was a direct reflection of treatment with pembrolizumab, a humanized antibody against the immune checkpoint inhibitor programmed death-1. With increasing use of immune-modulating drugs, this potential histological mimic may be seen more frequently in the future.
authors.affiliation: *Department of Anatomical Pathology, PathWest, QEII Medical Centre, Perth, Western Australia, Australia; †School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia; ‡Department of Medical Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia; §School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia; and ¶Margaret River Surgery, Margaret River, Western Australia, Australia.
authors.forename: Nathan Tobias
authors.initials: NT
authors.lastname: Harvey
authors.forename: Michael
authors.initials: M
authors.lastname: Millward
authors.forename: Kirstie
authors.initials: K
authors.lastname: Macgregor
authors.forename: Robert Paul
authors.initials: RP
authors.lastname: Bucat
authors.forename: Benjamin Andrew
authors.initials: BA
authors.lastname: Wood
mesh_terms: D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001706:Biopsy; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000188:drug therapy* / Q000276:immunology / Q000556:secondary; D055882:Nevus, Halo / Q000473:pathology*; D011237:Predictive Value of Tests; D061026:Programmed Cell Death 1 Receptor / Q000037:antagonists & inhibitors* / Q000276:immunology; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; C582435:pembrolizumab