Xanthomatous tendinosis.

The patient was a 26-year-old man referred to a physical therapist for a chief complaint of worsening bilateral knee pain in the region of the patellar tendons over the past 3 months that was insidious in onset. In an effort to further evaluate tendon morphology, the physical therapist pursued ultrasound imaging of the bilateral patellar tendons. It was determined that the ultrasound findings were compatible with xanthomatous tendinosis.