Baker's Cyst - Can you have one without being able to see it from the outside?

For 2 months, I've had terrible pain behind my knee, especially when I bend it.  My doctor has ordered an ultrasound to check for a Baker's Cyst - but no cyst is visible to the naked eye, nor can one be felt.  Is it still possible that a cyst exists?  

[Abhijeet Deshmukh, MD]

Hello.

Baker's cyst is a synovial sack enlarges to form a cyst. This may not be large enough to produce a visible bulge. Hence, in the beginning, the cyst my not be visible from outside.

Regards

[Patti66]

Thank you so much for you quick response.  I really appreciate it. :)

[janice05]

is a 5.6 cyst on the knee considered to be large

[babysteppeon]

Baker's Cyst are visible on MRI's has your doctor ordered one?

[dusan]

I had a baker's cyst several years ago and was given muscle relaxants and some pain meds. It resolved itself in a month.
  Last April I went to a clinic with similar pain and without even examining me, he said it was a Baker's cyst again. He gave me 60 Vicodan pills and sai when they were gone, my cyst would be too.
  I suffered for a month and the pain got worse, so I went to an orthopedic doctor and tests showed the bone in that knee had died, and I needed knee surgery to replace the bone with a space age material.
  So make sure the diagnosis is correct  or you may waste time and suffer a lot more pain needlessly like I did.

[skinandbones]

Is it normal for a bakers cyst to change size, and/or to have a feeling of more pressure on it?