Diagnostic Studies. Liposarcoma is best imaged by MRI and will have at least some fat with high signal intensity on T1-weighted images. Dedifferentiated liposarcomas will have a large area of fat except in the high-grade areas within the tumor that will be darker on T1-weighted images.

Treatment/Prognosis. Wide resection with a negative margin of greater than 1 cm is the standard of care for liposarcomas. In addition to lung metastases, liposarcomas have a higher chance of metastasis to the abdomen than other sarcomas.

MALIGNANT PERIPHERAL NERVE SHEATH TUMOR

Malignant peripheral nerve sheath tumor (MPNST) usually arises in a patient with neurofibromatosis. The distinction between the malignant area and the widespread neurofibromas in the patient with neurofibromatosis is difficult, particularly on imaging. PET/CT may be useful in this differentiation because the neurofibromas are usually of lower intensity on PET/CT than MPNSTs. Other benign tumors such as schwannomas do not have an increased incidence of malignant degeneration into MPNST. Wide resection with a negative margin of greater than 1 cm is the standard of care for MPNST. This will require the sacrifice of the nerve in which the tumor arose.