Survivor since 2007
The short answer is yes, you can have a lump might look like (and be) a fluid filled cyst on an ultrasound. Or a lump might have all sorts of appearances on an ultrasound. Are you asking if mistakes can be made and a cancerous lump might be mistaken for something benign? There are no absolute's when it comes to diagnostics. It is up to the eyes and experience of the radiologist/tech to differentiate between the make up of lumps. If there is the slightest bit of doubt, I would request further testing like a biopsy or an MRI. When dealing with your own health, you have to become your own best advocate. When in doubt... get a second opinion. Take care, Sharon
PS... my cancer was not found on a mammogram and was missed until I felt a lump 7 months later.