title: Atypical cellular blue nevus or malignant blue nevus?
abstract: Blue nevus is a benign melanocytic lesion whose most frequent variants are dendritic (common) blue nevus and cellular blue nevus. Atypical cellular blue nevus presents an intermediate histopathology between the typical and a rare variant of malignant blue nevus/melanoma arising in a cellular blue nevus. An 8-year-old child presented a pigmented lesion in the buttock since birth, but with progressive growth in the last two years. After surgical excision, histopathological examination revealed atypical cellular blue nevus. Presence of mitoses, ulceration, infiltration, cytological atypia or necrosis may occur in atypical cellular blue nevus, making it difficult to differentiate it from melanoma. The growth of blue nevus is unusual and considered of high-risk for malignancy, being an indicator for complete resection and periodic follow-up of these patients.
authors.affiliation: Division of Dermatology, Internal Medicine Department - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
authors.forename: Luise Ribeiro
authors.initials: LR
authors.lastname: Daltro
authors.affiliation: Department of Pathology - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
authors.forename: Lygia Bertalha
authors.initials: LB
authors.lastname: Yaegashi
authors.affiliation: Department of Pathology - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
authors.forename: Rodrigo Abdalah
authors.initials: RA
authors.lastname: Freitas
authors.affiliation: Division of Dermatology, Internal Medicine Department - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
authors.forename: Bruno de Carvalho
authors.initials: BC
authors.lastname: Fantini
authors.affiliation: Division of Dermatology, Internal Medicine Department - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
authors.forename: Cacilda da Silva
authors.initials: CD
authors.lastname: Souza
mesh_terms: D002648:Child; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D018329:Nevus, Blue / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology