Endometrial stromal sarcoma
Endometrial stromal sarcoma is a malignant subtype of endometrial stromal tumor arising from the stroma of the endometrium rather than the glands. There are three grades for endometrial stromal tumors, as follows. It was previously known as endolymphatic stromal myosis because of diffuse infiltration of myometrial tissue or the invasion of lymphatic channels.
Low-grade endometrial stromal sarcoma
Low-grade endometrial stromal sarcoma consists of cells resembling normal proliferative phase endometrium, but with infiltration or vascular invasion. These behave less aggressively, sometimes metastasizing, with cancer stage being the best predictor of survival. The cells express estrogen/progesterone-receptors.Undifferentiated uterine sarcoma
Undifferentiated uterine sarcoma, or undifferentiated endometrial stromal sarcoma, does not resemble normal endometrial stroma and behaves much more aggressively, frequently metastasizing. The differential includes leukemia, lymphoma, high-grade carcinoma, carcinosarcoma, and differentiated pure sarcomas.Pathology
Macroscopy
- Polypoid mass extending into broad ligament, ovaries and fallopian tubes.
- Lymphatic tumor plugs as yellow, ropy or ball-like masses.
Microscopy
- Monotonous ovoid cells to spindly cells with minimal cytoplasm.
- Prominent arterioles. Angiolymphatic invasion common.
- Up to 10-15 mitotic figures per 10 HPF in most active areas.
- Tongue-like infiltration between muscle bundles of myometrium.
- May exhibit myxoid, epithelioid and fibrous change.
- May have foam cells or hyalinization in the stroma.
Immunochemistry
- CD10+
- muscle markers positive in areas of smooth muscle differentiation
- CD117-
- h-caldesmon-