On the malignant spectrum, uterine sarcomas tend to occur in an older patient population when compared to leiomyomas, and only account for 3–7% of all uterine malignancies . They often present with the same symptoms as leiomyomas and thus cannot reliably be distinguished clinically.
Leiomyosarcomas (LMSs) are the most common uterine sarcomas, with an estimated annual incidence of 0.5–7/100,000 per women, followed by endometrial stromal sarcomas with an annual incidence of 1–2/million per women. Given that leiomyomas may currently be managed with minimally invasive treatment, it is particularly important to distinguish them preoperatively from confounding malignant entities such as LMSs. This is aimed to avoid inadvertent dissemination by laparoscopic, which should not be the treatment of choice, or delaying diagnosis with conservative management such as uterine artery embolization.
The misdiagnosis of a LMS for a benign leiomyoma could result in treatment delays and greater morbidity, given its poor prognosis and high propensity to locally recur and metastasize. On the basis of the FIGO 2009 classification, up to 68% of LMSs are diagnosed as stage I and only up to 22% are diagnosed as stage IV. Therefore, the imaging characteristics of the primary lesion, rather than secondary signs of malignancy, will ultimately help in differential diagnosis and drive treatment stratification. On average – 5-year survival rates ranging from 46–53%. Additionally, LMSs also have a 50–70% rate of recurrence, with up to 40% occurring in the lungs and up to 13% in the pelvis . Table 1. FIGO staging for uterine LMS (2009).