Review ArticleNon-Endometrioid Carcinomas of the Uterine Corpus: A Review of Their Pathology With Emphasis on Recent Advances and Problematic AspectsClement, Philip B MD*; Young, Robert H MD†Author Information From the *Department of Pathology, Vancouver General Hospital and Health Science Centre and the University of Columbia, Vancouver, British Columbia, Canada; and the †James Homer Wright Pathology Laboratories of the Massachusetts General Hospital, Harvard Medical School, Boston, MA. †Although these tumors have been traditionally referred to as “uterine papillary serous carcinoma”, we prefer the designation “endometrial serous carcinoma”. “Endometrial” is more precise than “uterine” and the tumors do not always have a papillary pattern. Indeed, serous carcinomas are defined fundamentally by their cellular characteristics rather than their architectural features. Correspondence: Philip B. Clement, MD, Department of Pathology Vancouver General Hospital, 910 W. 10th Avenue, Vancouver, B.C. V5Z 1M9 (e-mail: [email protected]). Advances in Anatomic Pathology: May 2004 - Volume 11 - Issue 3 - p 117-142 Buy Abstract This review considers the clinical and pathologic features of the various histologic subtypes of endometrial carcinoma excluding those of pure endometrioid type, as the latter tumors were the subject of a previous contribution in the Journal (Vol. 9, No. 2). Non-endometrioid carcinomas, which account for about 10% of endometrial carcinomas, may pose a great array of problems in differential diagnosis, including their distinction not only from benign lesions but also endometrioid carcinoma and various tumors that may secondarily involve the uterine corpus. The most common subtypes are serous, mucinous, and undifferentiated. Rarer tumors are clear cell, squamous, transitional cell carcinomas, and a variety of poorly differentiated carcinomas with unusual forms of differentiation, such as hepatoid carcinoma, carcinomas with trophoblastic elements, and giant cell carcinoma. Mixed carcinomas, which are common, are also discussed, including those with a component of endometrioid carcinoma. The final section deals with endometrial involvement by metastatic tumors, lesions that, albeit rare, are sometimes neglected in the differential diagnosis of endometrial carcinomas. Important aspects emphasized are: (1) The potential for serous carcinoma to be mimicked by various forms of papillary endometrioid carcinoma. (2) The rarity of clear cell carcinoma and the greater frequency of clear cells in endometrioid carcinoma. (3) The frequency of mucinous epithelium in tumors of mixed cell type. (4) The frequency with which neoplastic mucinous epithelium originates from the endometrium. (5) The striking degree of differentiation of some squamous cell carcinomas. (6) The occasional predominance of non-endometrioid carcinomas (especially serous or undifferentiated carcinoma) within malignant mullerian mixed tumors. (7) The spectrum of reactive epithelial changes and other non-neoplastic abnormalities that may mimic serous or clear cell carcinoma. © 2004 Lippincott Williams & Wilkins, Inc.