RT Journal Article SR Electronic T1 89 Large cell neuroendocrine carcinoma (LCNEC) of the endometrium : case report at hospital Sótero Del Río, Chile JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A46 OP A46 DO 10.1136/ijgc-2020-IGCS.84 VO 30 IS Suppl 3 A1 E Pertossi A1 N Saez A1 M Urzúa A1 P LeCerf A1 O Puga YR 2020 UL http://ijgc.bmj.com/content/30/Suppl_3/A46.abstract AB Introduction Type I endometrial carcinoma (EC) is the most common uterine cancer, with known risk factors as obesity. Type II EC is less frequent, with high risk histologies including LCNEC.Case A 62-year-old woman with type 2 diabetes, hypertension and obesity who had menopausal bleeding with an enlarged uterus, up to the umbilicus. CT-scan showed an enlarged uterus with a solid tumor filling the cavity and no evidence of dissemination. Endometrial sampling was performed with no evident dysplasia. Laparotomy revealed a 24 cm uterus and enlarged pelvic lymph nodes. TH+BSO was performed. Frozen section informed high grade carcinoma. Pelvic and para-aortic lymphadenectomy and omentectomy were then performed. Definitive pathology concluded a LCNEC of the endometrium infiltrating 93% of the myometrium with LVI+, without extrauterine spread (Stage IB). Afterwards, the patient received 6 cycles of etoposide plus cisplatin. To date, she’s been 20 months disease free.Discussion LCNEC of the endometrium has 28% 5-year overall survival. A recently published case series concludes that menopausal bleeding is the most common symptom. This aggressive histology has been included into type II EC, nevertheless, there is no consensus on pathologic criteria for diagnosis. WHO refers that diagnosis should be done with the presence of large carcinoma cells and high mitosis count, and presence of any of the following IHQ stains: chromogranine A, synaptophysin, CD56 or enolase enzyme. Here, the diagnosis was based on typical architectural large cells and CD56 positivity.