ABSTRACT
This chapter presents general clinicopathologic features of the endometrial cancers followed by descriptions of individual histologic types of the cancer. Endometrial cancers have long been classified into two major divisions (types I and II) based on light microscopic appearance, clinical behavior and epidemiology. Type I, those with endometrioid histology, comprise approximately 75% of newly diagnosed endometrial cancers in North America. In contrast, type II endometrial cancers have non-endometrioid histology, typically endometrial serous carcinoma (ESC) with an aggressive clinical course. ESC is less often associated with excessive prolonged estrogen exposure than endometrioid carcinoma. The majority of malignant endometrial neoplasms are adenocarcinomas. In practice, the diagnosis of endometrioid carcinoma with mucinous differentiation is appropriate if the malignant mucinous epithelia consist of less than 50% of total tumor volume. Approximately 60% of tumors are diffusely involved the endometrial cavity, presenting as thickening of the endometrium, polypoid or exophytic lesions.
