Pseudoangiosarcomatous squamous cell carcinoma of the skin: A need for a more rigorous nomenclature for histopathological variants of squamous cell carcinoma.

Over the years, squamous cell carcinomas (SCC) that mimicked vascular lesions have been encompassed within different classifications and the underlying etiopathogenic mechanisms have been interpreted in different ways by different authors. Here, we present a case of SCC with pseudovascular areas in the right leg of a 96-year-old woman with chronic venous insufficiency. Histopathological examination closely resembled an angiosarcoma, but the immunohistochemical negativity for endothelial markers and the strong positivity for the pancytokeratin marker AE1/AE3 revealed the epithelial nature of the neoplasm. After a comprehensive review of all similar previously published cases, we believe that it is necessary to separate SCC with pseudoluminal structures composed of glandular-like areas (pseudoglandular or adenoid SCC) from those mimicking vascular lumina (pseudovascular and pseudoangiosarcomatous SCC). We would like to emphasize that acantholytic SCC, a definitive variant of SCC, can be further classified into the common or ordinary subtype of acantholytic SCC, that shows solid nests containing numerous acantholytic atypical keratinocytes without any mimickers for specific structures, and pseudoglandular, pseudovascular and pseudoangiosarcomatous subtypes when glandular or vascular structures are mimicked, respectively.