uterine leiomyosarcoma

Uterine leiomyosarcomas are malignant uterine tumors that arise from the myometrium. The uterus is the commonest location for a leiomyosarcoma.

Epidemiology

Typically, these tumors present in women in the 6 decade. They account for up to one-third of uterine sarcomas but only ~8% of all uterine cancers .

Clinical presentation

Most commonly, patients present with abnormal vaginal bleeding, pelvic mass, and/or pelvic pain. Uncommonly, patients present with symptoms from local extension or metastases .

Pathology

Leiomyosarcomas mostly arise de novo  from uterine musculature or the connective tissue of uterine blood vessels, but can rarely arise from a pre-existing leiomyoma. The incidence of sarcomatous transformation in benign uterine leiomyomas is reported to be 0.1-0.8% .

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.

Histology can be similar to leiyomyosarcomas at other sites. A leiomyosarcoma is differentiated histologically from a leiyomyoma by noting the presence of infiltrative margins, nuclear atypia and increased mitotic figures.

Radiographic features

Generally, the uterus is often massively enlarged.

CT
  • may show irregular central zones of low attenuation, suggesting extensive necrosis and hemorrhage
  • foci of calcification may be present but rare
MRI

Although it has been suggested that an irregular margin of a uterine leiomyoma on MRI is suggestive of sarcomatous transformation, this is not considered that specific.

Treatment and prognosis

Surgical resection, followed by chemotherapy and/or radiotherapy, is the treatment of choice when possible. They generally carry a poor prognosis .

Differential diagnosis

Consider other uterine masses such as: