My sister age 61 has been diagnosed with congestive heart failure and is susposed to be taking water pills daily and she has not been doing now for several weeks. She is VERY overweight and also has severe swelling of her legs as has lipedema. Her legs are swollen about twice their normal size and stay swollen all the time but get worse when she sits for long time and stands for long time. The swelling is so bad that there is pouch all around the top of the ankle as this is how lipedema is because it runs in our family. The legs are swollen from hips on down to top of ankle. Just yesterday while I was at her home I noticed she had a very large lump about size of walnut protruding just on left food at below the ankle sort of a top of foot and she said it just formed that day and never had it before. She did not fall or have any injury to it. Could this be a blood clot or aneuroism or what?? I am very concerned about it because she just blew it off as nothing to be concerned about. Tell me what could it be?