Fig. 1: Dedifferentiated melanoma.
From: The clinicopathologic spectrum and genomic landscape of de-/trans-differentiated melanoma
This ulcerated tumor shows a nodular growth pattern within the dermis (a). It is composed of sheets of pleomorphic epithelioid cells with brisk mitotic activity (b). The adjacent epidermis shows melanoma in situ (c). The invasive tumor expresses CD10 (d) but it is negative for S-100 protein (e) and Melan-A (f). Melan-A staining also highlights the background of melanoma in situ (f).
