Serous endometrial intraepithelial carcinoma arising in adenomyosis: a report of 5 cases.

Serous endometrial intraepithelial carcinoma (serous EIC) arising in adenomyosis is rare. It may be underrecognized because of its deceiving morphology when embedded in the foci of adenomyosis. Although there is no connection to peritoneal cavity, some cases may be associated with extrauterine disease. It is currently unknown what the etiology for such a disease is. More studies are in need to elucidate the pathogenesis of such a grave malady. We report a series of 5 cases of serous EIC, which may arise in adenomyosis. The 5 cases are in 5 different patients or whom on histopathological examination of their hysterectomy specimens, the finding of adenomyosis involved with serous intraepithelial neoplasia was identified. The finding of interest was the presence of multifoci of adenomyosis; some of those foci were involved in serous EIC. In addition to EIC, lesions of endometrial glandular dysplasia were present in the foci of adenomyosis. To rule out the possibility of endometrial serous carcinoma (ESC) invading into the areas of the adenomyosis, all of the 5 uteri were extensively examined. Among the 5 uteri, the eutopic endometirum showed 1 invasive ESC, 2 serous EIC, and 2 benign resting endometrium without any cancer or precancerous lesions. In 1 uterus with ESC, we did not see any direct spatial connection between the invasive component of ESC and the areas of EIC in the foci of adenomyosis. In 2 uteri with serous EIC within the endometrial cavity, there was a distance of at least 0.5 cm between the lesions within the endometrial cavity and the serous EIC in adenomyosis. The remaining 2 uteri showed no evidence of endometrial malignancy in the endometrial cavity, whereas serous EIC was present only in areas of adenomyosis. Clinicopathologic data including characterized immunohistochemical stainings and p53 gene sequence analysis are presented and clinical significance is discussed.