ABSTRACT
A teenager has been bothered by a lump in her knee for some time. Generally it is not painful, but by the end of the day it becomes sore from rubbing against her other leg. She is otherwise healthy with no other complaints. On examination she has a firm, fixed protuberance above her left knee which is non-tender. The knee joint itself is normal; the overlying skin is normal, and her distal neurovascular exam is also normal.
