Benign and Premalignant Lesions of the Endometrium.

In this review, we highlight the benign and premalignant lesions of the endometrium that the pathologist may encounter in daily practice. We begin by detailing our current understanding of excess estrogen in the progression of endometrial neoplasia. We outline the currently accepted terminology to be used when evaluating proliferative endometrial lesions, while highlighting their key features. Attention is then turned to the molecular underpinnings of neoplastic progression and how this can be exploited with immunohistochemical stains when appropriate. Finally, we discuss types of metaplasia and their associations, including so-called papillary proliferations of the endometrium.