子宫内膜样癌（EC）占卵巢上皮肿瘤的大约10-12％，但与其相对频率相比，导致了不成比例数量的具有潜在误诊可能性的诊断困难病例。本综述讨论了卵巢EC多变和多样的形态学，包括“上皮转化”改变，具有纺锤细胞分化/编织和透明质化特征的EC，以及具有类性绒毛形态的EC。还讨论了卵巢EC的“转分化”倾向，其中一个例子是与某些来源为卵黄囊瘤的体细胞相关联。虽然免疫组化技术在诊断EC，区别EC和其他卵巢上皮肿瘤，转移性肿瘤和性索间质肿瘤方面可能非常有用，但本综述还讨论了卵巢EC表现出异常免疫表型的倾向，这可能加剧诊断不确定性。还讨论了这些肿瘤的基因组特征和最近将粘液性癌并入EC类别的“纳入”。版权所有©2023澳大利亚病理学皇家学院。由Elsevier B.V.出版。保留所有权利。

Endometrioid carcinoma (EC) accounts for approximately 10-12% of ovarian epithelial malignancies but compared to its relative frequency, results in a disproportionate number of diagnostically difficult cases with potential for misdiagnosis. In this review the protean and diverse morphologies of ovarian EC are discussed, including 'metaplastic' changes, EC with spindle cell differentiation/corded and hyalinised features and EC with sex cord-like formations. The propensity for 'transdifferentiation' in ovarian ECs is also discussed, one example being the association with a somatically derived yolk sac tumour. Although immunohistochemistry may be extremely useful in diagnosing EC and in distinguishing between EC and other ovarian epithelial malignancies, metastatic neoplasms and sex cord-stromal tumours, this review also discusses the propensity for ovarian EC to exhibit an aberrant immunophenotype which may compound diagnostic uncertainty. The genomic characteristics of these tumours and the recent 'incorporation' of seromucinous carcinoma into the EC category are also discussed.Copyright © 2023 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.