My 5 month old Tommy has these. I first noticed a small lump about an inch in from his ear when he was about 5 weeks old and mentioned it to the doctor who said it was a swollen gland. He now has 4 more of varying sizes - all low down on the back of his head. The largest feels like a small marble and you can move it around with your finger under the skin.
I went back to see the doctor today as they have been worrying me, and she seems pretty sure they're enlarged lumph nodes (and from doing a few searches online that certainly seems pretty likely). The odd thing is, Tommy is perfectly well and usually lymph nodes swell when fighting an infection or virus. The doctor seems to think it could be due to cradle cap, although Tommy only has a mild case, but I guess that could explain why they don't seem to be going down.
To be absolutely sure, the doctor is referring him to the paeds which I'm pleased about, as, like you, I really want to know for sure that this is nothing to worry about. However, the doctor insisted that she didn't think they were anything sinister and told me not to be concerned. To be honest, deep down I don't feel very worried, just a little uneasy.
How are Ethan's now? Any change? Have you requested a scan? I will post an update once Tommy's been checked out.
Christina