Endometrial cancer is the most common gynecologic malignancy and the fourth most common cancer among European and American women, accounting for 6% of new cancers and 3% of endometrial cancers. The age-adjusted annual incidence was 24.3 per 100,000 women in the United States in 2006-2010 and 19.4 per 100,000 women in the United Kingdom in 2008. 75% of endometrial cancers are early stage lesions (FIGOI-stage II) at the time of diagnosis. For patients with stages III-IV, 5-year survival rates were 57-66% and 20-26%, respectively. Traditionally, according to Bokhman’s classification, endothelial carcinoma is classified as type I, estrogen-dependent, associated with endothelial hyperplasia, and type II, non-estrogen-dependent, associated with endothelial atrophy. Endometrial cancers are classified according to histopathology as endometrioid, plasmacytoma, carcinosarcoma, and clear cell carcinoma. type I is mostly endometrioid and type II is overwhelmingly plasmacytoma. However, these associations are not perfect: type I endometrial carcinoma is associated with excess estrogen, obesity, hormone receptor positive status and endometrial hyperplasia, is moderately or highly differentiated and has a better prognosis; type II endometrial carcinoma is more common in non-obese women, occurs without endocrine and metabolic disturbances, is associated with endometrial atrophy and has a poorer differentiation and prognosis. Follow-up studies will hopefully elucidate the clinicopathological, histological and molecular correlations between type I and type II cancers. Diagnosis of endometrial cancer Most patients have abnormal vaginal bleeding (90%), mostly in late menopause. Diagnosis is often confirmed with outpatient curettage. 1 Surgical treatment is still the treatment of choice for endometrial cancer, and the role of surgical staging is to guide the selection of postoperative adjuvant therapeutic measures.1.1 Surgical methods 1) full staging surgery: including total hysterectomy, double adnexal resection, pelvic and abdominal washout cytology, pelvic and para-aortic lymph node dissection (or biopsy), the removal of ovaries is still controversial; 2) sub extensive hysterectomy + (2) subextensive hysterectomy + double adnexal resection or extended total hysterectomy + double adnexal resection: while removing the uterus and double adnexa, a portion of parametrial tissue and about 2 cm long vaginal vault is removed; (3) extensive hysterectomy + double adnexal resection: the operation includes the uterus, double adnexa, all parametrial tissue, and 3-4 cm long upper vaginal segment. 1.2 The standard surgery for stage I endometrial cancer is total hysterectomy + double adnexal resection. It is controversial whether to perform pelvic and abdominal aortic lymph node dissection, but it is meaningful to dissect lymph nodes in these high-risk patients. The main high-risk factors include deep muscle infiltration, hypodifferentiation, and non-endometrioid carcinoma. In contrast, some scholars believe that highly differentiated endometrioid carcinoma without muscle layer infiltration has almost no lymph node metastasis and can be treated without lymph node dissection. Patients with stage II endometrial cancer should be treated with: 1) transabdominal extensive total hysterectomy + double adnexal resection + pelvic in general, comprehensive surgical staging is necessary for patients with high-risk endometrial cancer. However, lymph node dissection and its associated complications may be avoided in low-risk patients. This study sought to evaluate the compliance of intraoperative frozen pathology with final paraffin pathology to estimate whether this could reliably guide the surgical approach intraoperatively in deciding whether to remove lymph nodes. 116 patients had a preoperative diagnosis of endometrioid adenocarcinoma or complex atypical hyperplasia. Demographic features and staging were collected, as well as pathologic grading and depth of myometrial infiltration on frozen and paraffin pathology sections. The results suggested that the compliance rate of histological subtype, grading, and depth of myometrial infiltration between frozen and paraffin sections was 97.5%, 88%, and 98.2%, respectively. 7 cases of frozen complex atypical hyperplasia were paraffin-confirmed as cancer, and 2 patients underwent reoperation. In conclusion, frozen pathologic analysis can be used as a guide for surgical decision to remove lymph nodes or not. The histologic subtype, grading, and depth of infiltration of the muscularis, with a high rate of compliance between frozen and paraffin sections, can be used as an indicator for intraoperative decisions on whether to perform lymph node dissection in patients.