Endometrial carcinoma (EC) accounts for about 4% of all cancers in women and affect mainly after menopause. In patients with EC, the pathologist plays an important role in establishing the prognosis and the need for postoperative adjuvant treatment. Based on the clinical behavior and etiology, ECs have been classified into two major classes: Type I and Type II. The Type I comprises relatively indolent tumors and represents the majority of sporadic ECs. Well and moderately endometrioid (G1 and G2) carcinomas are the prototype of the histological type I.
Type II accounts for about 10-20% of ECs, including most aggressive tumors. They are usually high-grade carcinomas (G3) with a serous or clear cell differentiation. This classification has an impact on prognosis, Type I being better when compared with Type II. In a following section, a brief description of the morphological features of the most important histological types is provided