A notable number of undifferentiated carcinomas were diagnosed as G3EC (19%; 7 of 36), which has a predominant, solid, sheetlike growth pattern with high-grade nuclear features, cellular dyshesion
, and increased mitotic activity and can overlap morphologically with G3EC.
Group 2--those with CISM lesions characterized by small and uniform cells, either growing in a solid pattern with focal microacinar-like structures but with cellular dyshesion
, or growing in a mosaic pattern with occasional intracytoplasmic vacuoles; Group 3--those with marked cellular pleomorphism and nuclear atypia, however, the LN discohesive pattern remains.
The striking dyshesion
of the UEC tumor cells makes lymphoma, plasmacytoma, and granulocytic sarcoma enter the list of the differential diagnoses.