| umls-concept:C1333280 | skos:definition | NCI: A rare form of malignant melanoma marked by nonpigmented lesions on sun-exposed areas of the body, most commonly on the head and neck.,NCI: A melanoma of the skin characterized by a proliferation of atypical spindled melanocytes in the dermis, in a background of abundant collagen. It usually presents as an amelanotic raised nodular lesion. | lld:umls |
