Objective Undifferentiated endometrial carcinoma (UEC) represents a recently recognized and rare diagnosis that is commonly misclassified on histopathologic evaluation. These cancers account for less than 10% of carefully reviewed series of endometrial cancers from academic medical centers. We reviewed a single-institutional experience with the management of UEC focusing on clinicopathologic characteristics and treatment outcomes.

Methods The medical records of all patients treated for histologically proven endometrial carcinoma between 2007 through 2016 were reviewed. Analysis was limited to 24 consecutive patients with histologically proven endometrial carcinomas that had at least a component of undifferentiated carcinoma on central pathology review. All patients were initially treated by definitive surgical resection. Grade 3 endometrioid carcinomas treated over the same period were used as a control group. The Kaplan-Meier method was used to estimate survival outcomes.

Results The median age at diagnosis was 66 years (range, 37–74 years). Ten patients presented with locally advanced or metastatic disease (42%). Fifteen patients (63%) received adjuvant chemotherapy with carboplatin and paclitaxel, 12 patients (50%) received adjuvant pelvic external beam radiation, and 10 patients (42%) received adjuvant vaginal cuff brachytherapy. With a median follow-up of 14 months (range, 0.5–115 months), 4 patients (21%) had developed disease recurrence and/or progression, 2 patients (11%) had died of disease, and 1 patient died of treatment complications. Twelve patients (63%) were alive with no evidence of disease at last contact. Outcomes were comparable to those with grade 3 endometrioid carcinoma.

Conclusions Our data are consistent with prior studies demonstrating that UEC represents a rare clinical entity characterized by high rates of locally advanced disease at presentation. However, survival outcomes appear to be comparable to other high-grade endometrial cancers. Further studies investigating optimal adjuvant therapy in these patients are warranted.