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Atypical cellular blue nevus or malignant blue nevus?
Luise Ribeiro Daltro1, Lygia Bertalha Yaegashi2, Rodrigo Abdalah Freitas2
1Division of Dermatology, Internal Medicine Department - Medical School of Ribeirão Preto - Universidade de São Paulo- Ribeirão Preto (SP) -Brazil.
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.
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