Unusual Patterns of Endometrial Carcinoma Including MELF and its Relation to Epithelial Mesenchymal Transition

Although most of Dr Scully's research addressed diseases of the ovary, about 10% of his published manuscripts focused on endometrial lesions, most often consisting of observations about unusual types or deceptive patterns of endometrial carcinoma that had not previously been described, or lesions for which the behavior had been unknown. He characterized and clarified the entity of clear cell carcinoma of the endometrium, and wrote about endometrial carcinomas with argyrophil, oxyphil, and giant cells, and those simulating microglandular hyperplasia of the cervix, as well as uterine papillary serous, squamous cell, and small cell carcinoma,. He provided a useful classification of precancers of the endometrium and also emphasized the relationship between estrogens and the development of some forms of uterine carcinoma. This article addresses the importance of his careful observations, focusing primarily on the potential relationship of 1 pattern of endometrial carcinoma that he described which has areas of microcystic, elongated, fragmented glands (MELF), frequently accompanied by a fibromyxoid or inflammatory stroma, to the recently described concept of epithelial mesenchymal transition. Endometrioid carcinomas with MELF frequently display a variety of immunohistochemical changes including reduced expression of E-cadherin, B-catenin, estrogen and progesterone receptors, Ki67, and overexpression of fascin, galactin-3, cyclin D1, and p16, as might be expected with epithelial mesenchymal transition. Additional studies will be needed to explain the significance of epithelial mesenchymal transition that occurs in carcinomas with regions of MELF.