A benign, small and slightly elevated brown or black skin lesion with usually well-demarcated borders. It is characterized by the presence of a melanocytic proliferation resulting in the formation of uniform cellular nests. Sometimes the clinical and morphologic features may be difficult to distinguish from melanoma. The disease is pigmented spindle cell nevus (MONDO_0006905, a Monarch Disease Ontology identifier). Also known as: spindle cell Nevus of Reed.