[emma_mcraf]

Oh Row, I'm so sorry to read this. You must be feeling overwhelmed with it all.
I have no experience of anything like this but assume an endoscopy to get samples would be less intrusive than a plastronoscopy, and then you'd have definitive answers as to what the mass is.
I know MBD isn't good but it can be prevented from worsening. I presume it's not very severe as I always think of Tetley in your videos and photos outside getting lots of natural sunlight and warmth and that you use supplements on his food.

Hopefully the anti-inflammatory meds are keeping him pain-free and he sounds mobile enough. I hope a little intervention will be enough as he's too young for you to have to say goodbye but I know you'll make the right decision for him.

Keeping everything crossed here that everything is treatable and thinking of you. xxx