Grading of epithelial ovarian carcinoma has always been somewhat problematic, with different systems proposed for different histopathologic types. Clear cell carcinoma (CCC) has been the most difficult to grade in a reproducible and clinically meaningful manner. A recently proposed “universal grading system” for all types of ovarian epithelial carcinoma has proven to be both reproducible and clinically relevant for all types except CCC, but problems have arisen with CCC, probably because mitotic activity as defined in this system is uniformly low in CCC and nuclear atypia (also a feature to be considered in the final grade) in CCC is rarely low. A newer system based on architectural features alone for the grading of CCC has been proposed, but has not yet been validated by independent observers. The World Health Organization (WHO) currently recommends that all CCCs should be considered high grade carcinomas.
KeywordsOvarian Epithelial Cancer Grade System Mitotic Activity Clear Cell Carcinoma Nuclear Atypia
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