Leiomyosarcoma of Uterus

Abstract

Leiomyosarcoma (LS) of uterus is the second most common uterine sarcoma, accounting for approximately 40% of all uterine sarcomas. Current studies support that LS of uterus is primary sarcoma, only less than 5% of them develop from malignant transformation of benign uterine fibroids. Pathologically, morphological features include apoptosis and necrosis, and cellular polymorphism can be used to differentiate LS from uterine fibroids and other small round cell tumors. Clinical symptoms are nonspecific, including abnormal vaginal bleeding, pelvic pain, and pelvic mass. The peak age of onset is the fourth to fifth decades, and only 15% of patients are younger than 40 years old. Previous radiotherapy history is the independent risk factor for LS of uterus [1, 2]. On MRI, imaging features vary based on its size and presence of necrotic components. In general, signal characteristics of LS show similarly to those of uterine fibroids, displaying as isointensity signal on both T1WI (Fig. 6.1) and T2WI (Fig. 6.2). Intratumoral hemorrhagic foci manifest as high signal on T1WI. Contrast-enhanced MR images (Fig. 6.3) show earlier enhancement than normal myometrium which can help to determine the location of the tumor (myometrium, endometrium or subserous) [3–5].