Uterine sarcoma

Overview
A uterine sarcoma is a malignant tumor that arises from the smooth muscle or connective tissue of the uterus. If the lesion originates from the stroma of the uterine lining it is an endometrial stromal sarcoma, and if the uterine muscle cell is the originator the tumor is a uterine leiomyosarcoma. A lesion that also contains malignant tumor cells of epithelial origin is termed uterine carcinosarcoma (formerly called malignant mixed mesodermal/mullerian tumor).

Prevalence
The vast majority of malignancies of the uterine body are endometrial carcinomas - only about 4% will be uterine sarcomas. Generally, the cause of the lesion is not known, however patients with a history of pelvic radiation are at higher risk. Most tumors occur after the menopause. Women who take long-term tamoxifen are at higher risk.

Signs and Symptoms
Unusual or postmenopausal bleeding may be a sign of a malignancy including uterine sarcoma and needs to be investigated. Other signs include pelvic pain, pressure, and unusual discharge. A nonpregnant uterus that enlarges quickly is suspicious. However, none of the signs are specific. Specific screening test have not been developed; a Pap smear is a screening test for cervical cancer and not designed to detect uterine sarcoma.

Diagnosis
Investigations by the physician include imaging (ultrasound, CAT scan, MRI) and, if possible, obtaining a tissue diagnosis by biopsy, hysteroscopy, or D&C. Ultimately the diagnosis is established by the histologic examination of the specimen. Typically malignant lesions have >10 mitosis per high power field. In contrast a uterine leiomyoma as a benign lesion would have < 5 mitosis per high power field.

Staging
Uterine sarcoma is staged like endometrial carcinoma at time of surgery using the FIGO cancer staging system.
 * Stage IA: tumor is limited to the endometrium
 * Stage IB: invasion of less than half the myometrium
 * Stage IC: invasion of more than half the myometrium
 * Stage IIA: endocervical glandular involvement only
 * Stage IIB: cervical stromal invasion
 * Stage IIIA: tumor invades serosa or adnexa, or malignant peritoneal cytology
 * Stage IIIB: vaginal metastasis
 * Stage IIIC: metastasis to pelvic or para-aortic lymph nodes
 * Stage IVA: invasion of the bladder or bowel
 * Stage IVB: distant metastasis, including intraabdominal or inguinal lymph nodes

Therapy
Therapy is based on staging and patient condition and utilizes one or more of the following approaches. Surgery is the mainstay of therapy if feasible involving total abdominal hysterectomy with bilateral salpingo-oophorectomy. Other approaches include radiation therapy, chemotherapy, and hormonal therapy.