High-grade ESS or undifferentiated endometrial sarcoma is a highly malignant neoplasm. Histologically, it exhibits greater than 10 MF/10 HPF and often completely lacks recognizable stromal differentiation. This tumor has a much more aggressive clinical course and poorer prognosis than endometrial stromal sarcoma (406,408,413–416). The 5-year disease-free survival is about 25%. Treatment of undifferentiated endometrial sarcoma should consist of total abdominal hysterectomy and bilateral salpingo-oophorectomy. The poor therapeutic results suggest that radiation therapy, chemotherapy, or both should be used in combination with surgery. These tumors, unlike endometrial stromal sarcoma, are not responsive to progestin therapy.
Uterine tumor resembling ovarian sex-cord tumor (UTROSCT) is a rare variant of endometrial stromal sarcoma in which benign glands and epithelial cells are found. Immunohistochemically, these tumors express cytokeratin, epithelial membrane antigen, vimentin, and smooth muscle actin. Although some of these tumors have infiltrative margins, almost all of them behave benignly. The so-called mixed UTROSCT have a significant endometrial stromal sarcoma component and tend to behave more aggressively (417,418).
Leiomyosarcoma The median age for women with leiomyosarcoma (43 to 53 years) is somewhat lower than for other uterine sarcomas, and premenopausal patients have a better chance of survival. This malignancy has no relationship with parity, and the incidence of associated diseases is not as high as in carcinosarcoma or endometrial adenocarcinoma. AfricanAmerican women have a higher incidence and a poorer prognosis than women of other races. A history of prior pelvic radiation therapy can be elicited in about 4% of patients with leiomyosarcoma. The incidence of sarcomatous change in benign uterine leiomyomas is reported to be between 0.13% and 0.81% (419–429).
Presenting symptoms, which are of short duration (mean, 6 months) and not specific to the disease, include vaginal bleeding, pelvic pain or pressure, and awareness of an abdominopelvic mass. The principal physical finding is the presence of a pelvic mass. The diagnosis should be suspected if severe pelvic pain accompanies a pelvic tumor, especially in a postmenopausal woman. Endometrial biopsy, although not as useful as in other sarcomas, may establish the diagnosis in as many as one-third of cases when the lesion is submucosal.
Survival rates for patients with uterine leiomyosarcoma range from 20% to 63% (mean, 47%). The pattern of tumor spread is to the myometrium, pelvic blood vessels and lymphatics, contiguous pelvic structures, abdomen, and then distantly, most often to the lungs. The number of mitoses in the tumor traditionally was the most reliable microscopic indicator of malignant behavior (Fig. 35.8).