Differentiating uterine sarcomas from mimickers on magnetic resonance imaging
Type:Educational Electronic Presentation
Authors: Marta Daniela Lameiras Costa, Rita Bem Pina Prata, Teresa Margarida Cunha
Keywords:uterine sarcoma; leiomyosarcoma; endometrial stromal sarcoma; undifferentiated uterine sarcoma; adenosarcoma; uterine leiomyoma; magnetic resonance imaging
Educational objective

- To review the clinico-pathological features of uterine sarcomas.

- To approach the most common appearances on magnetic resonance imaging of uterine sarcomas and discuss potential mimickers, namely the different subsets of leiomyomas with degeneration.

Topic Review

Uterine sarcomas represent a rare and heterogeneous group of tumours with aggressive behaviour, with an incidence of 0,7 in every 100,000 women (Van den Bosch T et al. 2012). According to the 5th edition of the WHO Classification of Tumours of Female Reproductive Organs, there are four main subgroups of sarcomas, namely: smooth muscle tumours, endometrial stromal tumours, mixed epithelial and mesenchymal tumours and miscellaneous mesenchymal tumours, the latter including other sarcomas like rhabdomyosarcomas, typically arising in the paediatric population.

Uterine sarcomas typically present as a rapidly growing pelvic mass in post-menopausal women with nonspecific clinical features. Morphological features in imaging studies vary in each of the tumours as will be discussed later. Serum tumour markers are usually within the normal range, although the nonspecific LDH...

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Figure 1. Pelvic MRI performed in a 71-year-old woman with vaginal bleeding and pelvic pain shows an irregular walled uterine tumour with high signal in the T2 weighted images including some foci suggesting necrosis (left images), heterogeneous enhancement (middle images) and high signal intensity in high b values of the diffusion study. This was a histologically proven leiomyosarcoma.
Figure 2. Pelvic MRI was performed in a 52-year-old woman who presented with a palpable abdominal mass and vaginal bleeding. It shows a heterogeneous uterine tumour in the posterior wall of the myometrium (left images), with high T2 weighted images (WI) signal intensity including central areas suggesting necrosis (left images), high signal areas in T1WI representing haemorrhage (best seen on sagittal fat suppressed T1WI, upper right) and restrictive behaviour in the diffusion study (middle images). This was a histologically proven leiomyosarcoma.e diffusion study. This was a histologically proven leiomyosarcoma.


Uterine sarcomas represent a rare and heterogeneous group of tumours with aggressive behaviour. MRI plays an essential role in the characterization and staging of tumours. An overlap in imaging features between sarcomas and leiomyomas with degeneration is often misleading. Differentiation between these entities is critical on imaging because uterine sarcoma requires a specific surgical technique to prevent dissemination.