Should endometrial clear cell carcinoma be classified as type II endometrial carcinoma?

Hyo Sook Bae, Hyesun Kim, Sun Young Kwon, Kyu Rae Kim, Jae Yun Song, Insun Kim

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39 Citations (Scopus)


Endometrial clear cell carcinomas (ECCCs) are considered to be Type II endometrial carcinomas, like uterine serous adenocarcinoma (SCA), and therefore aggressive clinical management is indicated. However, according to the limited clinical, immunohistochemical, and molecular data available in the literature, ECCCs show overlapping features of SCA and endometrioid adenocarcinomas. Therefore, questions regarding their designation as the Type II carcinomas have been raised. We performed immunohistochemical staining for hepatocyte nuclear factor-1β and napsin A for the histologic confirmation of clear cell carcinoma (CCC), and analyzed immunohistochemical findings for estrogen receptor, progesterone receptor, HER2/neu, p53, p16, ARID1A, PTEN, DNA mismatch-repair proteins along with other prognostic factors. We performed DNA sequencing for the K-RAS, BRAF, PIK3CA, and PTEN genes for 16 pure CCCs. No patients with pure CCC experienced recurrent disease or died of the disease (0/16, 0%). ECCCs had SCA-like features with rare expression of estrogen receptor/progesterone receptor (18.8%/6.3%) and no K-RAS mutations, intermediate features regarding expressions of p53 (37.5%) and p16 (25%), and endometrioid adenocarcinoma-like features regarding losses of PTEN (81.3%), ARID1A (25%) and mismatch-repair protein (68.8%), expression of microsatellite instability-high (25%), HER2/neu (12.5%), and PIK3CA mutations (18.8%). Pure ECCC should not be regarded as Type II carcinoma, because it shares the immunohistochemical and molecular characteristics of Type I endometrioid adenocarcinoma and Type II SCA.

Original languageEnglish
Pages (from-to)74-84
Number of pages11
JournalInternational Journal of Gynecological Pathology
Issue number1
Publication statusPublished - 2015 Jan 14
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014 International Society of Gynecological Pathologists.


  • Clear cell adenocarcinoma
  • DNA sequencing
  • Endometrial carcinoma
  • Endometrioid adenocarcinoma
  • Immunohistochemistry

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Obstetrics and Gynaecology


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