Knee Mets? Question for a friend

A friend (Stage IIIc, HER2 negative, ER/PR positive) is having great anxiety as she just had the results of an MRI to the knee, where she has been having great pain. The radiologist found something suspect and has suggested she get a bone scan. She is very worried that it's cancer. I've searched this site and can't find any references to knee mets. Any information would be appreciated.