The cytological features of the plasmacytoid included large, discohesive, isolated tumor cells with abundant, thick cytoplasm, and eccentrically located, hyperchromatic nuclei with coarse chromatin and inconspicuous nucleoli. The discohesive nature of this tumor is consistent with the known clinical phenotype. The immunohistochemical profile of the plasmacytoid variant was positive for pan-CK, CK7, CK20, and negative for vimentin, LCA, S-100 protein, CD138, and E-cadherin.
The key features of the micropapillary variant were papillary cell clusters arranged in a honeycomb, floral cauliflower pattern with high-grade nuclear features, dense cytoplasm, moderate to severe nuclear atypia. These cases were positive for CK20, CK7, PTEN, MUC1, E-Cadherin, and negative for CDX2, MUC5A, and MUC6.
Recent studies identified key genomic features of both plasmacytoid and micropapillary variants. The current study adds to our understanding of the morphological and phenotypic markers of these aggressive variants.
Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine, New York City, New York
1. Straccia, Patrizia, Maurizio Martini, Emilio Sacco, Pier F. Bassi, and Francesco Pierconti. "Cytological features of micropapillary and plasmacytoid variants of urothelial carcinoma." Diagnostic cytopathology 48, no. 2 (2020): 111-117.
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