Keywords:
Neoplasia, Education, MR, CT, Musculoskeletal soft tissue, Anatomy
Authors:
C. Azzopardi, G. Kiernan, M. Gibbons, J. Teh; Oxford/UK
DOI:
10.1594/essr2018/P-0153
Conclusion
There are no specific imaging features to accurately distinguish the subtypes of lipomatous tumours radiologically.
Abdominal liposarcomas with a paucity of fat can be diagnostically challenging.
There are five distinct histologic subtypes of soft tissue liposarcomas: well differentiated,
dedifferentiated,
myxoid,
pleomorphic,
and mixed type.
Well differentiated liposarcomas present as a predominantly lipomatous mass with some non-lipomatous components in the form of thick septa or focal nodules.
A large nodular component suggests dedifferentiated liposarcoma,
and biopsy should be directed at this component.
Myxoid liposarcoma has a high water component,
however a small amount of fatty tissue seen in septations or as nodules points towards a lipomatous tumour.
Pleomorphic liposarcomas are high-grade lesions and are heterogeneous on imaging studies with only small amounts of fat content [5].
The diversity of lipomatous tumours is not only seen in their imaging appearances but also in their clinical and biologic behaviour.
This ranges from well-differentiated liposarcomas,
which are generally non-metastatic to high-grade neoplasms such as pleomorphic liposarcomas which has extensive metastatic potential [5].
The role of imaging is to define the primary tumour and the extent of local invasion.
Features that suggest unresectable disease include extensive vascular involvement,
peritoneal implantation,
and distant metastatic disease [4].
As can be seen in the cases presented intra-abdominal and retroperitoneal liposarcomas usually present late as large masses.
The large size means complete surgical resection is often not possible.
This results in recurrence rates that approach 100% within 6 months-2 years of initial surgical resection and local recurrence is the primary cause of most morbidity and mortality [4].
The presentation of liposarcomas as hernias provides an opportunity to review the relevant anatomy whilst delineating the imaging characteristics of these soft tissue sarcomas.