Brown Line on Mom's Nail Turns Out to Be Rare Form of Melanoma Adult and Pediatric Nail Unit Melanoma: Epidemiology, Diagnosis, and Treatment 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 Subungual Melanocytic Lesions: Key Clinical and Pathologic Concepts and Biopsy Techniques Actas Dermo Sifiliogrficas