Atypical cellular blue nevus or malignant blue nevus?* * Study conducted at Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto- Universidade de São Paulo (FMRP-USP) - Ribeirão Preto

Luise Ribeiro Daltro Lygia Bertalha Yaegashi Rodrigo Abdalah Freitas Bruno de Carvalho Fantini Cacilda da Silva Souza About the authors


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.

Melanoma; Nevus, blue; Nevus, pigmented

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