Case 5 possessing EIC in both endometrial polyp and endometrium, but with stromal invasion in the polyp (A. Pap × 20, B. Pap × 60, C. HE × 20, D. HE × 60). A. A carcinoma cell cluster is accompanied by a bloody background. B. Carcinoma cells having enlarged nuclei appear to be transitional with normal atrophic cells having small-sized nuclei (arrows). C. The polyp has many atypical glands with intraluminal papillary protrusion of the carcinoma cells. D. The border between the carcinoma cells and normal cells is clearly discernible (arrows). There are small carcinoma nests showing stromal invasion (arrowheads).
Yasuda et al. Diagnostic Pathology 2013 8:25 doi:10.1186/1746-1596-8-25