Mehregan et al.

 
"Histological features in the early, or radial, phase [of melanoma] consist of extensive proliferation of large melanocytic cells with abundant and dusty cytoplasms [sic] at the dermoepidermal junction. There is a great tendency for junctional nest formation. Mitotic figures are present, and upward transmigration of small nests or individual atypical melanocytes within the epidermis is common. Extensive transepidermal elimination of large melanocytic cells is characteristic of the pagetoid variety. A lichenoid tissue reaction with basal cell damage associated with a lymphohistiocytic infiltrate is observed in the clinically white, regressive areas. The upper dermis shows fibroplasia, macrophages containing melanin, and patchy lymphocytic and plasma cell infiltrate . . ." Mehregan A, Hashimoto K, Mehregan D, Mehregan D. Pinkus' guide to dermatohistopathology. 6th Edition. Connecticut: Appleton and Lange, 1995:502–3.
 

Brief Critique

 
Pagetoid melanocytes in pagetoid pattern within the epidermis is a sign of melanoma, but that finding is not come upon in most specimens of it. All of the other changes detailed are found in some Spitz's nevi.