In 2006, dedifferentiated endometrioid adenocarcinoma (undifferentiated carcinoma associated with low-grade endometrioid carcinoma) of the uterus was first proposed. Dedifferentiated endometrioid carcinoma is part of the spectrum of undifferentiated carcinoma of the endometrium which is a highly aggressive tumor even when the undifferentiated component represents only 20% of the entire neoplasm. Therefore, accurate diagnosis and appropriate classification of this neoplasm are important in patient management. Lack of the recognition may lead to misclassification of dedifferentiated endometrioid adenocarcinoma as a pure endometrioid adenocarcinoma which is less aggressive. Only 4 papers have appeared in the literature so far on the topic of dedifferentiated endometrioid carcinoma. We report herein a first case of endometrial dedifferentiated endometrioid carcinoma in a 51-year old woman in Chinese population. We performed immunoperoxidase studies for 12 markers. Among them, cytokeratins, keratin 7, keratin 18, EMA, estrogen receptor (ER), progesterone receptor (PR), and vimentin show significantly differential expression between differentiated and undifferentiated area.
Keywords: Endometrium; dedifferentiated endometrioid adenocarcinoma; endometrioid adenocarcinoma; undifferentiated carcinoma.