CASE 3406 Published on 13.07.2005
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Retroperitoneal liposarcoma: Spiral-CT findings and multi planar reconstruction images

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Anzidei M, Rengo M

Connected authors
Patient

63 years, male

Categories
No Area of Interest ; Imaging Technique CT, CT, CT, CT
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Clinical History
A 63-year-old male patient presented with an extrinsic colon compression, which was identified during a routine screening colonoscopy.
Imaging Findings
A 63-year-old male patient, completely asymptomatic, presented to our hospital to undergo a virtual colonoscopy screening of the colon. The examation, when done, evidenced the presence of a large (having a maximum diameter of 20 cm), solid mass with regular edges and central necrotic areas (in a context of fat-like and muscle-like signal intensity), located infront of the left kidney; the mass was found to compress and displace the descending colon and a part of the small bowel. The appearence of this neoformation strongly matched with the average CT scan features seen in the case of a retroperitoneal liposarcoma.
Discussion
A liposarcoma is a malignant tumor that has an embryologic origin from the mesodermal tissue and,even if it accounts only for 0.1% of all tumors, seen in humansbeings, it is the most commonly seen histological subtype of the rare retroperitoneal soft tissue neoplasms. A liposarcoma can be of four histological subtypes: (a) well-differentiated, with lipoma-like and/or sclerosing components (50%); (b)myxoid, with highly hydrated cells (30%); (c) pleomorphic, and (d) round cell, which present as a heterogeneous non-fatty mass (10%); This tumor grows slowly, and the symptoms often appear late: A diffuse abdominal pain is the most frequent symptom, and the presence of an abdominal mass is the most common sign, while compressive manifestations in relation to other abdominal organs are more rare. The prognosis is severe, with a survival rate of upto 5 years, variable from 12% to 50% in different studies (the average survival rate is 4 years and 2 months). A very important prognostic factor is the degree of growth of the tumor and the possibility of surgical treatment. En-bloc surgical ablation is basic, to achieve a complete resection and disease control, but is a challenging procedure due to the large size of tumor, a retroperitoneal location and a multiorgan involvement, the resection of several contiguous structures is required and there often persists a high risk of microscopic residual disease. Intraoperative radiotherapy is perhaps able to offer some advantages in the local control of the disease and in improving the survival rate. The occurrence of distant metastases are rare, while local recurrence is usually more frequent and often shows an even more aggressive behavior than the primitive disease, with a higher tendency to penetrate into the adjacent organs. A good follow-up of the patients is necessary; diagnostic and preoperative studies involve the CT and MRI scans. A CT is performed before and after iodate c.a. injection: each histological subtype of an abdominal liposarcoma shows a different attenuation, but the predominant pattern seen is a mixed fat-like and muscle-like signal intensity. The presence of thick septa and necrotic areas are even common findings, while calcification or ossification are more rare, but significant adverse prognostic factors. A spiral CT technique is also useful in performing MPR (Multi Planar Reconstruction), which is a powerful tool for investigation of tumor contiguity, its relationship with the other organs, and the eventual invasion of them. Moreover, the CT technique provides both an imaging modality and a method to obtain tissue for diagnosis: a histological diagnosis is essential in treatment planning and adequate tissue for this purpose can usually be obtained by a CT-guided core biopsy. MRI specificity and sensibility are similar to those of the CT technique, but the soft tissue resolution capacity is more. Images are mainly obtained with T1-, T2-, and fat-suppressed T1-weighted methods, before and after the administration of gadopentetate dimeglumine. A careful assessment of the margins and internal characteristics (degree of contrast enhancement of the septa, the presence of nodular or patchy nonadipose components, zones of necrosis) is basic to characterize the lesion. The differential diagnosis must be, made with the possibility of leiomyosarcoma, rabdomyosarcoma, teratoma and neuroblastoma.
Differential Diagnosis List
Retroperitoneal liposarcoma.
Final Diagnosis
Retroperitoneal liposarcoma.
Case information
URL: https://www.eurorad.org/case/3406
DOI: 10.1594/EURORAD/CASE.3406
ISSN: 1563-4086
Figure 1

Fig.1

Fig.1
A spiral-CT scan of the abdomen on an axial plane showing the presence of a dishomogeneous mass in front of the left kidney.
Figure 2

Fig.2

Fig.2
An image on the coronal plane showing the cranio-caudal extension of the mass, which is seen reaching the left iliac fossa.
Figure 3

Fig.3

Fig.3
The image acquired on the sagittal plane showing clearly the antero-posterior expansion of the mass that occupies the entire left part of the abdominal cavity, with several necrotic areas within the tumoralso being seen.
Figure 4

Fig.4

Fig.4
A 3D Multiplanar Reconstruction(MPR) clearly showing how the mass(right side of the image) dislocates a part of the small bowel(left side), and its realationship with the endoperitoneal fat(not infiltrated) and the muscular wall of abdomen.
Fig.4
An MPR on the coronal plane demonstrating more clearly the adhesion of the neoplastic structure to the muscular abdominal wall.