[Solved]: A 52-year-old man presents to the primary care…

A 52-year-old man presents to the primary care practice with pain in his left calf that has been increasing in intensity over the past 3 days. He reports no fever, recent illness, or injury, and he has not recently traveled. He says the pain is a 9 out of 10 on the pain scale and describes it as a tight sensation behind his knee that is worse when he extends his left leg. The left lower leg and foot are pink and warm to touch, and there is marked edema of the posterior knee and calf. There is full range of motion of the left knee and no grinding or crepitus with flexion or extension. A round, fluctuant, tender mass is felt behind the knee when the patient is in the prone position. Which of the following is the most likely diagnosis?