title: Malignant melanoma arising in a blue nevus with features of pilar neurocristic hamartoma.
abstract: A 65-year-old man presented with a history of a giant blue plaque of the parietal scalp since childhood. Biopsy revealed a cellular blue nevus. The blue nevus was observed for 10 years and thought to be unchanged until a new adjacent lesion was noted. Biopsy of the new lesion revealed metastatic malignant melanoma. A wide excision was performed of the original lesion which revealed malignant melanoma arising in a blue nevus. Areas within the blue nevus were consistent with a pilar neurocristic hamartoma, whereas other areas were consistent with a common blue nevus. Subsequent satellite metastases developed, with early metastases resembling blue nevi except for the absence of a stromal component and the presence of hyperchromatic nuclei. Later metastases were typical of metastatic melanoma. This case illustrates the uncommon evolution of malignant melanoma from a blue nevus. The histological features and relationship between melanoma, blue nevus, and pilar neurocristic hamartoma are reviewed.
authors.affiliation: Department of Dermatology, Cleveland Clinic Foundation, Ohio.
authors.forename: A L
authors.initials: AL
authors.lastname: Pathy
authors.forename: T N
authors.initials: TN
authors.lastname: Helm
authors.forename: D
authors.initials: D
authors.lastname: Elston
authors.forename: W F
authors.initials: WF
authors.lastname: Bergfeld
authors.forename: R J
authors.initials: RJ
authors.lastname: Tuthill
mesh_terms: D000368:Aged; D006201:Hair Diseases / Q000473:pathology*; D006222:Hamartoma / Q000473:pathology*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000556:secondary; D016609:Neoplasms, Second Primary / Q000473:pathology*; D009432:Neural Crest; D018329:Nevus, Blue / Q000473:pathology* / Q000556:secondary; D012536:Scalp Dermatoses / Q000473:pathology*