I had a haematoma the size of an egg in my calf once when a twat of a neurologist punctured an artery. It remained connected to the artery and eventually formed a chamber that pulsated with my heartbeat. We had a surgeon sharpening up his Swiss penknife when it clotted through, almost overnight, and was then resorbed in a week or two. I could hardly walk for a month, and the curmudgeonly bugger didn't even reply to my doc's letter of complaint.