Fig. 13.1 The variable histological appearances of MIS. (a) Intraepidermal pagetoid scatter of cytologically atypical melanocytes containing abundant melanin (×10). (b) Intraepidermal pagetoid scatter of cytologically atypical, but less pigmented…

Fig. 17.1 Metastatic melanoma involving the subcapsular sinus Fig. 17.2 Metastatic melanoma involving the lymph node parenchyma Immunohistochemistry may be very helpful when examining SLN. As with melanomas at other…

Common acquired nevi Dysplastic nevi Melanoma Well nested at peripheral junctional component (circumscribed) Mild–moderate: circumscribed Single-cell, non-nested melanocytes predominate Moderate–severe: poorly circumscribed Maturation (senescence) transition from pigmented nested melanocytes in…

Women 20–40 years old Back > face, extremities History of biopsy or excision, with or without free margins Appear within weeks–months after excision Pigment usually within margins of scar Pigment fades with…

Fig. 15.1 Nodular malignant melanoma with an adjacent associated nevus Another criterion favoring the interpretation of a primary rather than metastatic melanoma is the presence of regressive features, including an…

Fig. 3.1 Compound congenital melanocytic nevus: in addition to nests, there is a proliferation of single cells dispersed along the epidermal basal layer, which lack significant cytologic atypia (a). Malignant…

Fig. 14.1 Comparison of desmoplastic nevus (left) and desmoplastic melanoma (right). Desmoplastic nevus, as some Spitz nevi do, may show many cells expressing HMB45 antigen in the dermis; however, anti-Ki67…

Fig. 8.1 Nevoid malignant melanoma. (a) The lesion displays circumscription, but cellular crowding (×10). (b) Note nuclear pleomorphism. Mitotic figures are scattered in the lesion including its base (×40). (c)…

Fig. 4.1 Distinction between nevus and melanoma. (a) HMB45 labels the intraepidermal and upper dermal components of this large compound nevus. In contrast (b) melanoma cells show strong, but patchy…

Fig. 7.1 Comparison of halo nevus (a) and superficial spreading melanoma with focal regression (b). Low magnification; exophytic, symmetrical melanocytic lesion with a dense, regularly distributed, lichenoid infiltrate that obscures…