Salivary gland infection/cyst?

[CaptainKit]

I have a vet appointment for tomorrow lunchtime, so will soon have a professional's opinion, but thought I'd post here in the meantime to see if Dr Google and I have come up with a semi-possible diagnosis, or if salivary gland infections are super rare and I should just wait and see what the vet says.

CapPup is an 8 1/2 month old lurcher; somewhere halfway between whippet and greyhound heights. Other than a few destructive tendencies, and the occasional wee on the kitchen floor, he's grown into a real sweetie. He's a rescue, but no nasty back story - just an unwanted puppy bought by an idiot and then swiftly handed in to the nearest rescue. I've had him since he was 12 weeks old, he had stomach issues when he was little, but has been fine for months now.

I was giving him a bit of a fuss, as you do, and noticed that under his jaw/chin, closer to his neck than his nose, there is a soft fatty lump about the size of an egg split lengthwise - not a hard growth, but something squishy. He didn't seem to have an issue with me gently poking and prodding. I can't see any disturbance to the fur, or any breaks in the skin, so I don't think it's a playfighting wound which has become infected.

Temperament-wise he's unchanged; all bouncy and active as usual; tearing around the place. He was sick once on Saturday, but has otherwise been completely normal, so I think that might just be his lurcher tendency to eat anything and everything rather than an additional symptom. he had half normal food and half white rice yesterday dinner and this morning just in case there was going to be more, but he scoffed the lot both times with no further sign of tummy troubles.

Anyone any experience with anything like this? I'm assuming, if I'm on the right lines then it'll be anti-biotics; a drain for the cyst if we're really unlucky.

Lumps in this area can be a huge number of things including lymph nodes. Without feeling even as a professional it is impossible to tell my list is at least ten items long based on your description.
In the nicest possible step away from Dr Google 90% of the time Google diagnoses are wrong.

Ah yes, those pesky lymph nodes are around there too. Although I'd assumed swollen lymph nodes would be a little lower down, and there might be two lumps if both were enlarged. However my lymph knowledge is all centred in having had ferrets with lymphoma, and there's a slight difference in anatomy between ferrets and dogs!

If only I could step away from Dr Google. I trust my vets, and have been with them for long enough and over a variety of animals, so wouldn't be second guessing them, and wouldn't be looking to treat an unwell pet based off of my own very limited knowledge, but it makes me feel more prepared if at least some of the things they talk about tomorrow are things I've already read about. Just takes away a bit of the uncertainty. (Disclaimer: I am one of those people who looks up pretty much everything; research makes me feel a bit less out of control.) Same reason why I'm posting here - it helps manage any anxiety.

Pictures added, partly because he's such a pretty scruff, and partly to show off my MS paint arrows!

As you say he chews things a foreign body would be very high up my list.

Yeah, that would make sense. Have added 'foreign body' to my mental list of things it could be. Also briefly entertaining the possibility of his needing to be knocked out so the vet can get a better look. Coming away with abs is still my hope, but am prepared for more having to be done.

I've gently opened his mouth, not to look for anything, so much as to check his reactions ahead of the vet having a poke and prod tomorrow. No real reaction, which is good. I do try to get the dogs used to being inspected; checking paws and ears and eyes etc. His breath doesn't smell infectiony, but that doesn't mean anything.

Vet had a good look/feel, which Pup wasn't so keen on. She confirmed there's nothing inside the mouth; no wound or source of infection. From what she could feel of the lump itself she's thinking that he's possibly hit it on something, or it's been caught by another dog (quite possible - he's a loopy lurcher and he loves to run and play fight with other dogs, so I could believe that he managed to hit his head in the throes of some exciting game.)

I've been given an anti-inflammatory - Metacam - to give for a few days; if this doesn't cause the swelling to go down then it's back to the vets for a biopsy. Given that Pup didn't really like being poked and prodded by the vet, I can't imagine he'll sit nicely for a needle biopsy, so is likely to need to be sedated so they can get what they need. I'm hoping it doesn't come to that.