TRIGGERED TRAP - NEVOID MALIGNANT-MELANOMA

Nevoid malignant melanoma probably represents an early form of nodular malignant melanoma in which there is little proliferation of melanocy tes in the epidermis and a dermal proliferation that mimics some featu res of a compound or intradermal nevus, which is difficult to recogniz e as being due to malignant melanoma, The lesions can contain either s mall nevoid cells or larger cells that resemble those in Spitz's nevi, Overall the lesions are symmetrical, have minimal proliferation in th e epidermis, and often have dispersion of cells at the base, The lesio ns with small nevoid cells are particularly difficult to distinguish f rom common intradermal or compound melanocytic nevi, Reactivity of the intradermal component for HMB-45 antigen, without antigen retrieval, or for Ki-67 antigen can show that the dermal cells have an immature p henotype and, in combination with histological criteria, can support a diagnosis of nevoid malignant melanoma, Copyright (C) 1998 by W.B. Sa unders Company.