Uterine sarcomas: clinical presentation and MRI features

Abstract

Uterine sarcomas are a rare heterogeneous group of tumors of mesenchymal origin, accounting for approximately 8% of uterine malignancies. They comprise leiomyosarcoma, endometrial stromal sarcoma, undifferentiated endometrial sarcoma, and adenosarcoma. Compared with the more common endometrial carcinomas, uterine sarcomas behave more aggressively and are associated with a poorer prognosis. Due to their distinct clinical and biological behavior, the International Federation of Gynecology and Obstetrics introduced a new staging system for uterine sarcomas in 2009, categorizing uterine carcinosarcoma as a variant of endometrial carcinoma, rather than a pure sarcoma. Magnetic resonance imaging (MRI) has a developing role in the assessment of these malignancies. Features such as tumor localization, irregular or nodular margins, necrosis, rapid growth, intense contrast enhancement, and restriction at diffusion-weighted imaging can suggest the diagnosis and help differentiate from more common leiomyomas and endometrial carcinoma. MRI is therefore extremely useful in preoperative detection and staging and, consequently, in determination of appropriate management. This pictorial review aims to discuss the clinical features of uterine sarcomas, as well as their most common appearances and distinct characteristics in MRI.

Figure 1.

a–c. Leiomyosarcoma in a 52-year-old woman. Sagittal T1-weighted image (a), T2-weighted image (b), and gadolinium-enhanced T1-weighted image with fat suppression (c) show marked uterine enlargement due to a heterogeneous myometrial tumor. The lesion demonstrates central hyperintensity on T1-weighted image (a) attributable to extensive hemorrhage, a central area of high signal on T2-weighted image (b) representing cystic necrosis, and early intense enhancement in solid areas of the tumor (c, arrow), as compared with normal myometrium. Irregular central zones of low signal intensity (asterisk) suggest extensive tumor necrosis. Endometrial cavity is pushed anteriorly by the tumor (b, arrow).

Figure 2.

a, b. Leiomyosarcoma in a 54-year-old woman. Axial DWI on b1000 (a) demonstrates a hyperintense mass. The mass appears hypointense on ADC map (b, asterisk), with the normal myometrium seen as an area of hyperintensity (arrows).

Figure 3.

a, b. Endometrial stromal sarcoma in an 82-year-old woman. Sagittal T2-weighted image (a) and sagital T1-weighted image with fat suppression, after contrast administration (b) show a very large lesion centered at cervix region, infiltrating uterine body superiorly and superior half of the vagina inferiorly. The tumor shows multiple foci of hyperintense signal on T2-weighted image due to extensive necrosis, as well as moderate and mildly heterogeneous contrast enhancement.

Figure 4.

a, b. Sagittal (a) and axial (b) T2-weighted images show an endometrial stromal sarcoma in a 64-year-old woman. The lesion shows heterogeneous signal with extensive nodular invasion into the myometrium and marked marginal irregularity and nodularity (attributable to tumor extension along vessels and lymphatics).

Figure 5.

a, b. Undifferentiated endometrial sarcoma in a 36-year-old woman. Sagittal T2-weighted image (a) and T1-weighted image after gadolinium administration (b) show marked uterine enlargement due to a large polypoid heterogeneous tumor, with some nodular marginality (arrow). The lesion shows intense and heterogeneous contrast uptake (uncommon for endometrial carcinoma), with a hypointense area (asterisk) suggestive of necrosis.

Figure 6.

a, b. Adenosarcoma in a 76-year-old woman. Sagittal T2-weighted image (a) and oblique coronal T1-weighted image with fat suppression, after contrast administration (b) show a very large polypoid mass with heterogeneous high signal intensity arising within the endometrial cavity and protruding into the cervical os (arrow), causing marked enlargement of the uterus. The tumor demonstrates a multicystic appearance (asterisk), with solid areas demonstrating enhancement similar to myometrium.