Should have said April ... not June

Most likely, they are just being careful. Before I had my thyroid biopsy, they said even if it was benign, they'd probably do a second biopsy just to be sure, but there would be no rush for that.

I don't think there is likely to be much to be worried about. It sounds like they just want to double check and the odds of them finding anything worrying are extremely low.

Even in the worst case situation, thyroid cancer is usually comparatively easily treated anyway. Not that any form of cancer is something you want, but the most common forms have close to 100% survival rate, especially at your son's age and rarely, if ever, require chemo or radiotherapy.

But it doesn't sound like that is at all likely here anyway.

It's always worrying to have to undergo any tests, but you should be really reassured by the fact that he already got a benign result.