Endometrial stromal sarcoma
|This article relies largely or entirely upon a single source. (May 2010)|
|Endometrial stromal sarcoma|
|Classification and external resources|
Endometrial stromal sarcoma is a rare endometrial tumor arising from the stroma (connective tissue) 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.
Endometrial stromal nodule
An endometrial stromal nodule is a noninfiltrative, circumscribed proliferation of endometrial stromal cells. The appearance of the cells is identical to normal stromal cells. This can only be differentiated from low-grade sarcoma by confirming lack of infiltration.
The differential includes cellular leiomyoma. Diagnosis may be aided by immunostaining; endometrial stromal nodules are positive for CD10; leiomyomas are positive for caldesmon and desmin (and sometimes CD10).
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 more aggressively, sometimes metastasizing, with cancer stage the best predictor of survival. The cells express estrogen/progesterone-receptors.
Undifferentiated uterine sarcoma
Undifferentiated uterine sarcoma, or undifferentiated (high-grade) 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.
Cytologic and genetic features
A recurrent chromosomal translocation, t(7;17)(p15;q21), occurs in endometrial stromal sarcoma. This translocation leads to the fusion of two polycomb group genes, JAZF1 and JJAZ1, with production of a fusion transcript with anti-apoptotic properties. Interestingly, even normal endometrial stroma cells express the fusion gene, derived not by translocation, but by the "stitching" together of m-RNAs. Thus, it appears that a pro-survival gene in the normal endometrium is somehow subverted to become pro-neoplastic.
- Sternberg's Diagnostic Surgical Pathology, 5th edition, p. 2242-2245.
- Kumar V, Abbas A, Fausto N, Aster J (2010). Robbins and Cotran Pathologic Basis of Disease. 8th edition. Philadelphia: Elsevier Saunders
- Li H et al (2009). "Gene fusion and RNA trans-splicing in normal and neoplastic cells". Cell Cycle.