8790/0 Cellular blue nevus


ICD-O-3 topography code: C44

Cellular blue naevus (CBN) is a dermal/subcutaneous pigmented tumour characterized by a multinodular cellular infiltrate with a dumb-bell architecture. The cellular infiltrate is composed of spindle-shaped melanocytes with pale cytoplasm alternating with bundles of pigmented spindle-shaped melanocytes. Foci of elongated slender melanocytes resembling Schwann cells, which indicate neurotization, are a frequent observation. In occasional cases an increased mitotic activity, focal necrosis, and nuclear pleomorphism may be seen. Such cases with atypical features may have an uncertain malignant potential. CBN has a wide anatomical distribution, but shows a predilection for the buttocks and sacral region. The tumours present as large (1 to several cm), slowly growing, light blue-brown to dark blue, non-ulcerated firm nodules.
Cellular blue nevus typically manifests in young adults (2nd to 4th decades of life) with a female predilection. The lesions are generally benign, but some cases with atypical features have resulted in recurrences or death from systemic metastasis. Treatment of choice is therefore complete excision and long-term follow-up1
LeBoit PE, Burg G, Weedon D, Sarasin A (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Skin Tumours
3rd Edition
IARC Press: Lyon 2005