Anatomic Pathology: Gynecologic Pathology

• Most endometrioid endometrial carcinomas are associated with precursor hyperplasia, demonstrate low Ki-67 and p53 expression, and express estrogen receptor and progesterone receptor. However, a subset of lesions demonstrates high Ki-67 and p53 expression, similar to uterine serous carcinomas, and these lesions have a poorer prognosis.

• Roughly one third of endometrioid endometrial carcinomas harbor K-ras mutations.

• In one study, the combination of high survivin expression, low p21 expression, and the presence of microsatellite instability predicted a poor prognosis. Survivin is a member of the inhibitor of apoptosis family. p21 is a cell cycle regulator.

• Although most FIGO stage I carcinomas have an excellent prognosis, a subset of tumors in which the combination of high survivin expression and low p21 expression was found had a much poorer prognosis. This subgroup accounts for approximately 20% of FIGO stage I endometrial carcinomas.

• Endometrioid endometrial carcinomas have a microsatellite instability pathway similar to colorectal carcinogenesis. High microsatellite instability colorectal carcinomas are well known to demonstrate hypermethylation. Hypermethylation also appears to be a frequent event in early endometrial carcinogenesis.