Apictorial guide to various types of retroperitoneal sarcomas (RPS) highlighting important imaging features which can help the radiologist to differentiate histological subtypes. Toidentify key patterns of disease behaviour of some of the more common RPS. To demonstrate the radiologist's role in diagnosis, assessing resectibility and staging.

Various pathologies may arise in the retroperitoneum including primary and secondary neoplasms. Primary retroperitoneal tumours (benign and malignant)are rare. These are tumours that originate within the retroperitoneum but separate to the retroperitoneal organs. Retroperitoneal sarcomas (RPS) are very uncommon, malignant tumours of mesenchymal origin that are responsible for approximately one third of retroperitoneal neoplasms. The radiologist can play a pivotal role in management byaiding diagnosis and assessing tumour resectibility. Key information includes the location of the tumour, its size and the adjacent structures (relationship to...

Liposarcomas Liposarcomas (LPS) are usually well-differentiated containing abnormal fat but withdedifferentiated components which appear more solid. Other types such as myxoid, pleomorphic and mixed type also occur but are less common. Well Differentiated Liposarcomas (WDL) - have imaging characteristics similar to fat. They tend to have nodular septations internal vascularity and a heterogenous texture. De-differentiated Liposarcomas (DDL) - usually have well defined solid components that are distinguishable from the fatty tissue. Leiomyosarcoma Leiomyosarcoma's are the second most common primary RPS. It is an uncommon malignant...

RPS consist of a variety of sarcoma subtypes, with liposarcomas the most common. This pictorial review helps illustrate some pertinent imaging features that can help characterise the particular sarcoma, although tissue typing with a percutaneous biopsy remains the gold standard. In addition to this, imaging can provide the surgical team with valuable information with regards to tumour resectability and staging.

Hartman et al. Leiomyosarcoma of the retroperitoneum and inferior venacava: radiologic-pathologic correlation. Radiographics1992; 12(6):1203-1220. PMID: 1439022 O'sullivan et al. Radiological imagingfeatures of non-uterine leiomyosarcoma. Br J Radiol 2008;81(961):73-81 Goldman et al. The varied radiographic manifestations of retroperitoneal malignant fibrous histiocytoma revealed through 27 cases. J Urol 1986 Jan; 135 (1): 33-8 Wignall et al. Solitary Fibrous Tumours of the Soft Tissues: Review of the Imaging and Clinical Features with Histopathologic correlation. AJR 2010; 195:W55-W62. Nishino et al.Primary retroperitoneal neoplasms: CT and MRI findings with anatomic...

Dr Dariush Douraghi-Zadeh MBBS FRCR Radiology SpR Department of Radiology Royal Marsden Hospital, London, UK email: [email protected] Dr Khawaja Shahabuddin MRCP FRCR Radiology Fellow Department of Radiology Royal Marsden Hospital, London, UK email:[email protected] Dr Robert Thomas MRCP FRCR Radiology Fellow Department of Radiology Royal Marsden Hospital, London, UK Dr Eleanor Moskovic FRCP FRCR Consultant Radiologist Department of Radiology Royal Marsden Hospital, London, UK