Fig. 3

Atypical Spitz tumors with MAP3K8 fusion. a Dome-shaped, mainly dermal proliferation with a myxoid stroma and lymphocytic infiltrate. b Close-up view of a. Cluster of large multinucleated cells with ample cytoplasm. c Dome-shaped, mainly dermal proliferation with epidermal hyperplasia. d Close-up view of c. Plexiform infiltration of large epithelioid melanocytes without maturation. e Dome-shaped, predominantly dermal proliferation. f Dense dermal nests of large epithelioid melanocytes with giant multinucleated cells. g Regional loss of p16 expression in the more cellular area. h FISH shows loss of CDKN2A (green) compared to reference probe (red). i Dome-shaped, mainly dermal proliferation with deep-dermal nodules. Hyperplasia of the epidermis with central erosion and crust. j Close-up view of deep-nodule with hyperpigmented, spindled, and epithelioid melanocytes