89 Primary endometrioid adenocarcinoma of the cervix: a diagnostic dilemma

Introduction/Background Primary endometrioid adenocarcinoma (EAC) of the cervix is a rare type of invasive endocervical adenocarcinoma with a prevalence of 1.1% based on the International Endocervical Adenocarcinoma Criteria and Classification. To date, there are 4 cases of non-HPV-associated primary cervical EAC reported and little is known about its clinical behaviour given its rarity. Differentiating it from primary endometrial adenocarcinoma is challenging due to overlapping clinical and morphological features, but important as the management differs. Methodology We describe the diagnostic dilemma in a case of non-HPV-associated primary EAC of the cervix in a postmenopausal woman. Endometrial curettings favoured an endometrial primary in view of the endometrioid subtype. Pre-operative imaging revealed a suspicious 1.8cm cervical tumour but no endometrial lesions. She underwent an open modified radical hysterectomy, bilateral salpingo-oophorectomy and bilateral pelvic lymph node dissection. Intra-operatively, the cervix felt hard but no obvious tumour was seen. Final histology revealed poorly differentiated EAC, centered entirely in the cervix, without any endometrial pathology (Pictures A-C). Combined with the immunohistochemical profile of absent block nuclear p16, mutant p53 with patchy ER and vimentin positivity (Pictures D-F), the constellation of findings were in keeping with primary cervical cancer. The patient underwent adjuvant radiotherapy. We reviewed the available literature on primary cervical EAC, to identify common clinical features and histopathological and immunohistochemical markers, which could aid in determining the site of origin. Results Primary cervical EACs tend to occur in postmenopausal women, with larger tumours diagnosed at higher stages. They are frequently associated with lymphovascular invasion, lymph node metastasis, and local and distant recurrences. Immunohistochemical markers such as p16, vimentin and ER are helpful in obtaining an accurate pre-operative diagnosis. Conclusion Diagnosing primary cervical EAC prior to definitive surgery is challenging. A combination of clinical, radiological and histopathological features with the use of immunohistochemistry is often required to clinch the diagnosis. Disclosures All authors declare no competing interests.