Metastatic myxoid liposarcomas: imaging and histopathologic findings.
OBJECTIVE
The objective was to describe the imaging and histopathologic characteristics of metastatic myxoid liposarcomas.


METHODS
This retrospective study was approved by the institutional review board and complied with HIPAA guidelines. The study group comprised 12 patients with metastatic myxoid liposarcoma who underwent MRI, CT, or FDG-PET. The location and imaging characteristics of the metastatic lesions were recorded, and the histopathology of all metastatic lesions was reviewed.


RESULTS
There were 23 histologically proven metastases in 12 patients. Based on imaging criteria, there were 41 metastases. The mean time from the diagnosis of primary tumor to the first metastasis was 4.4 years. Sixty-seven percent of patients had bone and soft tissue metastases, 33% had pulmonary metastases, 33% had liver metastases, 25% had intra-abdominal, and 16% retroperitoneal metastases. CT demonstrated well-defined lobulated masses with soft tissue attenuation in all cases, without macroscopic fat component. In cases of osseous metastases, CT showed mixed lytic and sclerotic foci, with bone destruction in advanced cases. MRI demonstrated fluid-like signal intensity with mild heterogeneous enhancement in cases of soft tissue metastases. In osseous metastases, MRI showed avid heterogeneous enhancement. FDG-PET showed no significant FDG uptake for all metastases. MRI was the most useful imaging modality for osseous and soft tissue metastases.


CONCLUSIONS
Myxoid liposarcomas are soft tissue sarcomas, with a high prevalence of extrapulmonary metastases. The bones and soft tissues were the most common site of involvement, followed by the lungs and liver. MRI was the most sensitive modality in the detection of osseous and soft tissue metastases, and is the recommended modality for the diagnosis and follow-up of bone and soft tissue involvement.
Sheah
Kenneth
K
Department of Radiology, Massachusetts General Hospital, 55 Fruit Street, YAW 6E, Boston, MA 02114, USA.
Ouellette
Hugue A
HA
Torriani
Martin
M
Nielsen
G Petur
GP
Kattapuram
Susan
S
Bredella
Miriam A
MA
D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D018208:Liposarcoma, Myxoid / Q000000981:diagnostic imaging / Q000556:secondary*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18