S15C4P2-1: Tumor cells (and giant cells) are immunoreactive for S-100 protein.

S15C4P2-3: Red arrows point to nests of loosely aggregated cells within clear spaces. The nests are arrayed linearly; one nest extends to the inked margin of excision. The patterns are compatible with lymphatic permeations.

S15C4P2-4: At a higher magnification, atypical cells are loosely clustered in a clear rounded space. A well-defined layer of endothelial cells is not a feature, but the linear array of nests of cells at a uniform depth in the dermis is compatible with lymphatic permeations.

S15C4P2-5: The patterns are sarcomatoid. The lesions has invaded the subcutaneous fat; this feature qualifies the lesion as an aggressive variant.

S15C4P2-6:This is a separate focus of tumor in the dermis; it is separate from the main tumor. The patterns are sarcomatous. In the category of a pleomorphic sarcomatoid melanoma, this isolated lesion qualifies as a satellite lesion (a dermal metastasis).