"pseudocystic: homogeneous density between –20 and +20 HU"
"They are usually seen in the extremities (75%), most commonly the thigh, and are less commonly seen in the retroperitoneum, groin or elsewhere 2,9 (see: retroperitoneal liposarcoma)."
"Low-grade lesions (atypical lipomas) are almost entirely fat signal with however thick septa, enhancement or evidence of local invasion. These features are used to distinguish these from simple lipomas 2."