Endometrial stromal sarcoma is a malignant subtype of endometrial stromal 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.

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 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 Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ...

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enla ...

, high-grade carcinoma,

carcinosarcoma Carcinosarcomas are malignant tumors that consist of a mixture of carcinoma (or epithelial cancer) and sarcoma (or mesenchymal/connective tissue cancer). Carcinosarcomas are rare tumors, and can arise in diverse organs, such as the skin, salivary ...

, and differentiated pure

sarcomas A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal (connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sarco ...

Pathology

Macroscopy

* Polypoid mass extending into

broad ligament The broad ligament of the uterus is the wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis. Structure Subdivisions Contents The contents of the broad ligament include the following: * Reprod ...

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

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 ( muscle specific actin MSA, smooth muscle actin SMA and

desmin Desmin is a protein that in humans is encoded by the ''DES'' gene. Desmin is a muscle-specific, type III intermediate filament that integrates the sarcolemma, Z disk, and nuclear membrane in sarcomeres and regulates sarcomere architecture. Str ...

) positive in areas of smooth muscle differentiation *

CD117 Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 (cluster of differentiation 117) or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding diff ...

- (c-kit -) * h-

caldesmon Caldesmon is a protein that in humans is encoded by the ''CALD1'' gene. Caldesmon is a calmodulin binding protein. Like calponin, caldesmon tonically inhibits the ATPase activity of myosin in smooth muscle. This gene encodes a calmodulin- and ac ...

Genetic features

A recurrent

chromosomal translocation In genetics, chromosome translocation is a phenomenon that results in unusual rearrangement of chromosomes. This includes balanced and unbalanced translocation, with two main types: reciprocal-, and Robertsonian translocation. Reciprocal translo ...

, t(7;17)(p15;q21), occurs in endometrial stromal sarcoma. This translocation leads to the fusion of two

polycomb Polycomb-group proteins (PcG proteins) are a family of protein complexes first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place. Polycomb-group proteins are well known for silencing Hox genes ...

group genes,

JAZF1 Juxtaposed with another zinc finger protein 1 (JAZF1) also known as TAK1-interacting protein 27 (TIP27) or zinc finger protein 802 (ZNF802) is a protein that in humans is encoded by the ''JAZF1'' gene. Variants are associated with an increased risk ...

and JJAZ1, with production of a fusion transcript with anti-apoptotic properties. 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.

References

External links

{{Medical resources , DiseasesDB = , ICD10 = , ICD9 = , ICDO = , OMIM = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeshID =
Webpathology

Gynaecological cancer