 EIN should not be confused with an unrelated entity, serous intraepithelial carcinoma ("serous EIC"), which is an early stage of a different tumor type known as papillary serous adenocarcinoma that also occurs in the same location within the uterus.The average age at time of EIN diagnosis is approximately 52 years, compared to approximately 61 years for carcinoma.The timeframe and likelihood of EIN progression to cancer, however, is not constant amongst all women.