Received: 6 September 2017
Accepted: 7 October 2017
Imaging in retroperitoneal soft tissue sarcoma
Department of Radiology, The Royal
Marsden Hospital London and The Institute of
Cancer Research, London, UK
Department of Radiology, Fondazione IRCCS
Istituto Nazionale Tumori Milan, Milan, Italy
Christina Messiou, MD, Department of
Radiology, The Royal Marsden Hospital
London and The Institute of Cancer Research
NHS funding to the NIHR Biomedical
Research Centre at The Royal Marsden
Patients with retroperitoneal sarcoma can present to a variety of clinicians with non-
specific symptoms and retroperitoneal sarcomas can be incidental findings. Failure to
recognize retroperitoneal sarcomas on imaging can lead to inappropriate management
in non-specialist centers. Therefore it is critical that the possibility of retroperitoneal
sarcoma should be considered with prompt referral to a soft tissue sarcoma unit. This
review guides clinicians through a diagnostic pathway, introduces concepts in response
assessment and new imaging developments.
CT, diagnosis, MRI, retroperitoneum, soft tissue sarcoma
Retroperitoneal soft tissue sarcomas (RPS) are frequently
incidental findings on imaging for non-related symptoms or
diseases and can grow to a large size in the retroperitoneum
before symptoms or signs of abdominal pain, back pain, bowel
obstruction or a palpable abdominal mass develop. RPS are rare
and account for approximately 12-15% of all soft tissue sarcomas
with a mean incidence of 2.7 per million.
radiologist and clinicians involved in the patients care at
presentation may not have experience of the imaging appearances.
management in inexperienced centres. This can have catastrophic
consequences due to incomplete resections or contamination of
the patients peritoneal cavity with tumor which jeopardizes the
patients chance of a curative operation.
After tumor grade, the
long-term survival following RPS resection is most dependent on
the completeness of surgical resection. Other important factors are
patient age, tumor subtype, tumor size, multifocality, and central-
ized multidisciplinary management in a specialist sarcoma cen-
Therefore early referral is advisable.
DIAGNOSTIC IMAGING TECHNIQUES
Computed tomography (CT)
CT allows confirmation of site and origin of the mass and often tissue
composition ie, lipomatous elements, calcifications or myxoid
elements. Particularly where large masses distort anatomy, distinc-
tion between peritoneal and retroperitoneal masses can be
challenging however displacement of retroperitoneal organs is a
useful indicator that a tumor is retroperitoneal.
local soft tissue infiltration and the relationship to critical
neurovascular structures and the presence of metastatic disease
are essential for surgical planning. Therefore contrast-enhanced
computed tomography (CT) is the most useful primary imaging
investigation with the additional benefit of wide availability.
However it has been shown that with the exception of well
differentiated liposarcoma and angiomyolipoma, the correct diagno-
sis of a retroperitoneal mass based on imaging alone is very
Percutaneous core needle biopsy usually confirms the
diagnosis and is the gold standard, but rarely lesions are not
amenable or high risk for biopsy and the differential diagnosis based
on imaging becomes crucial.
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© 2017 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.
J Surg Oncol. 2018;117:25–32. wileyonlinelibrary.com/journal/jso