[Myxoid liposarcoma. MRI imaging].
OBJECTIVE
Myxoid liposarcoma is the most common type of liposarcoma (approximately 40 to 50% of all liposarcomas). The main tissue component is a myxoid matrix present primarily in extracellular compartments; proliferating lipoblasts account for less 10% of the tumor: MRI appearances are not typical for lipomatous tumor. Nevertheless histological features may permit understanding MRI findings and identifying patients with myxoid liposarcoma.


METHODS
Clinical history and radiologic images of 7 patients with histologically verified myxoid liposarcoma were retrospectively studied. In all patients the tumor presented in a lower extremity as a painless, slowly growing mass. MR images were available for review in all cases (T1- and T2-weighted images); in addition fat-suppression before and after gadolinium enhancement were assessed with T1-weighted sequences.


RESULTS
MRI examination revealed an "encapsulated" tumor, non infiltrating and septated. On T1-weighted sequences all the lesions show lacy, amorphous and linear foci of high signal within a low signal of the tumor due to the predominance of a myxoid matrix. The high sensitivity of MRI demonstrates the presence of small areas of high signal and fat-suppression technique is valuable for characterizing soft-tissue tumors: suppression of high signal intensity on fat-saturated T1-weighted images indicates the presence of fatty tissue components.


CONCLUSIONS
Clinical correlation with MRI appearances on T1-weighted sequences (in addition to fat-suppression technique) may suggest the possibility of myxoid liposarcoma.
Soulié
D
D
Service de Radiologie, Hôpital d'Instruction des Armées du Val-de-Grâce, Paris.
Boyer
B
B
Lescop
J
J
Pujol
A
A
Le Friant
G
G
Cordoliani
Y S
YS
D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007866:Leg; D018208:Liposarcoma, Myxoid / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000473:pathology
Liposarcome myxoïde. Aspects en IRM.