Inverted Papillary Uroth. CA, High-Grade : Molecular Genetics

Comments:
Molecular Genetics: Like their exophytic counterparts, high-grade urothelial carcinomas with inverted growth pattern carry molecular alterations in FGFR3, TERT promoter, TP53, CDKN1A, PIK3CA, and chromatin-modifying genes. These alterations are rare to non-existent in inverted urothelial papilloma (IUP). On the other hand, IUPs harbor oncogenic HRAS or KRAS missense mutations which are rarely seen in urothelial carcinomas with inverted growth pattern.

This image of inverted papillary urothelial carcinoma, high-grade, shows branching, irregular, thick trabeculae composed of pleomorphic cells in the lamina propria.