Cellular blue nevus – A challenging entity: Case report.

Blue nevi can present clinically as blue, gray, brown, or black solitary nodules or plaques on the skin. Histologically, they represent collections of melanocytes and melanophages in the dermis. We presented here a case of a cellular blue nevus in a 20 years old man that presented as an enlarging blue-gray nodule on the right buttock. These cases can be challenging both clinically and histologically because malignant melanoma or malignant transformation of a blue nevus could be considered.