Can a liposarcoma appear as a lipoma on ultrasound? and do they cause sharp pain? can they occur in the arm?

No pain: Liposarcomas can arise where ever fat is present in the abdomen and extremities. When malignant transformation occurs it does not do so uniformly throughout a relatively large lesion. To be sure of pathology whole lesion should be resected and one can find lipoma with select areas of malignant transformation as well as myxomatous components.Pain is rarely associated with lipoSa. Sono of no value