Subungual Melanocytic Lesions: Key Clinical and Pathologic Concepts and Biopsy Techniques Actas Dermo Sifiliogrficas Brown black pigmented nail bands (melanonychia) can be a sign of subungual melanoma. This case report describes a child with melanonychia mimicking melanoma caused by green slime. Presumably, the slime embedded in the Melanotic macule of nail unit and its clinicopathologic spectrum ScienceDirect Dermoscopy of a nail matrix nevus in a 5 year old child. Brown Download Scientific Diagram Longitudinal melanonychia in a 13 year old Caucasian boy