I have discovered recently a lymph node I didn't know existed in deer (in over 25 years of stalking) and it was pus filled. Added to that I could find nothing when I researched online hence my sharing it. The axillary LN is in the shoulder joint, the armpit in effect. I have to say thank you to two vets on here who responded to my email within hours.
The scene was: I shot a mature roe doe and checked all of the normal lymph nodes plus lungs, liver, spleen etc and all were 100% OK as well as no chest adhesions. She was a good weight, was carrying plenty of fat and twin foeti.
It was only when I came to bone out the shoulder that I discovered pus (off white, no odour) in what I thought was a joint but she was not lame hence the email to the vets. The vet explained there is a LN there as in humans (where this is in the armpit that can swell with infection/disease.) See photos below with point of knife indicating position of (incised) lymph node in first photo and the second pic on the right indicating the consistency and amount of pus.
The conclusion was that with only the axillary node affected the infection was sterile and probably caused by trauma rather than disease. I explained we suffer badly from fence injuries on the estate in question and that could well have been a likely cause. She did have hair missing from her brisket but obviously in early March they are starting to change their coat so it could have just rubbed off. TB was ruled out as all of the lymph nodes in the respiratory tract were 100% clear and, again the axillary was alone in being affected. The deer was not culled in or near a TB wildlife observation zone.
As I only butcher a relatively small amount of the deer I cull (selling the rest or getting the dealer/butcher to process them in to burgers/sausages/mince etc) this could be why I have never encountered this LN before. It's small and easy to miss, only the pus indicated it's presence.
I'd be interested if anyone else has encountered enlarged or infected axillary LNs in deer.