Evolution of a trophoblastic tumor from an endometrioid carcinoma--a morphological and molecular analysis.

We report the clinicopathological and molecular characteristics of a rare uterine endometrioid carcinoma with a nongestational trophoblastic neoplastic component that was composed of both choriocarcinoma and epithelioid trophoblastic tumor. Molecular genetic analysis showed a clonal evolution from endometrioid carcinoma to trophoblastic tumor. The findings from this case have both diagnostic and biological implications that may inspire future studies on the pathogenic mechanisms by which cancer stem cells assume aberrant differentiation programs and the molecular switch(es) that initiates trophoblastic differentiation in adult tumor tissues.