dysplastic nevus (EFO_0004199, an Experimental Factor Ontology identifier) is clinically atypical nevi (usually exceeding 5 mm in diameter and having variable pigmentation and ill defined borders) with an increased risk for development of non-familial cutaneous malignant melanoma. Biopsies show melanocytic dysplasia. Nevi are clinically and histologically identical to the precursor lesions for melanoma in the B-K mole syndrome. (Stedman, 25th ed). Also known as: dysplastic nevi, dysplastic nevus syndrome, nevus syndrome, dysplastic.