Fig. 6: Spitzoid melanomas with NRAS mutation.
From: Spitz melanoma is a distinct subset of spitzoid melanoma
a Low power view of case 6 which harbors NRASQ61H with high-level focused amplification the mutant allele shows a dome shaped compound tumor with epidermal hyperplasia and clefting around nests of melanocytes in the superficial dermis. (b) The lesion is composed of epithelioid melanocytes with hyperchromatic nuclei, growing as nests and fascicles distributed between thickened sclerotic collagen bundles. (c) Whole genome copy number profile demonstrates NRAS amplification as well as loss of chromosome 1p distal to NRAS and gain of chromosome 1q. (d) Low power view of case 25—which harbors NRASQ61K, CTNNB1G34I, IDH1R132C, and NFKBIE and TERT promoter mutations shows a nodular tumor that extends to the deep dermis. (e) The lesion is predominantly composed of large epithelioid melanocytes with focal areas of small more nevoid cells, predominantly near the dermal-epidermal junction. (f) Many dermal mitoses are present (arrows).
