Synovial hemangioma of infrapatellar (Hoffa) fat pad: Magnetic resonance imaging and ultrasound features

The infrapatellar fat pad (IFP) also known as Hoffa fat pad, an intracapsular extrasynovial structure readily visualized on magnetic resonance imaging of the knee,1 can be affected by a variety of pathologic conditions (lipoma, hemangioma, synovial chondromatosis, focal villonodular synovitis, ganglion cyst, osteochondroma, and chondrosarcoma).2 Because synovial hemangioma is an extremely rare disease and often shows nonspecific symptoms (pain, swelling, limping, or limitation of motion), diagnosis could be delayed in many cases.3 Ultrasound is acknowledged to be of considerable value in assessing superficial masses around the knee joint.