[1223] Mesonephric-Like Endometrioid Glandular Proliferations: A Morphologically Distinct Form of Metaplasia

Lorraine Y Pan, Frank N Moore, Teri A Longacre. Stanford University, Stanford, CA

Background: Endometrioid proliferations exhibit a wide variety of morphological variants, including spindled, corded, sertoliform, and microglandular. We have recently encountered a form of endometrial metaplasia that demonstrates morphology reminiscent of mesonephric hyperplasia in the uterine cervix, similar to that previously described as a deceptive pattern of cervical invasion by endometrial carcinoma. Herein we describe the features associated with this unique form of metaplasia.
Design: A total of 14 cases featuring discrete proliferations of small, rounded and uniform tubules with cytologically bland nuclei were identified by retrospective review of recent consultation files. H&E stained slides were reviewed and each case was classified as simple metaplasia, hyperplasia, or carcinoma. In selected cases, immunohistochemical studies were performed to confirm endometrial origin with a panel of 3 markers (ER, vimentin, p16).
Results: Of the 14 cases, 8 were associated with carcinoma, 3 were associated with hyperplasia and 3 were associated with benign processes. In each case, the characteristic glands were small, somewhat crowded in relation to the adjacent uninvolved endometrium, and round or tubular in contour. The gland lumens often contained pale staining, occasionally dense eosinophilic secretions. Nuclei were only mildly atypical, but mitotic figures were almost always present. The gland clusters tended to occur in the basalis of the endometrium or lower uterine segment, intermingling with normal uninvolved glands and sparing the superficial zone even when associated with an endometrioid carcinoma.
Conclusions: Mesonephric-like endometrial glandular proliferations represent a unique form of metaplasia, often arising along the basalis of the endometrium. This predilection for basalis and lower uterine segment (which may reflect a muted response to prevailing hormonal mileu) may account for the previously recognized unusual microglandular pattern of cervical spread by some endometrioid carcinomas.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 126, Tuesday Afternoon


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