Small growth slightl;y below outside of right hock joint. Anyone dog had this before? - Page 2

It is possible it is callus a search for photo of calluses to see if it looks like it.

“Often called pressure sores, dog elbow (hock, etc.) calluses appear as a result of your dog's overprotective ulna bone protecting the bony part that pokes out. Continual trauma caused by your dog flopping down on the aforementioned cool tile, or any hard surface, causes the skin to thicken to protect the bone.”

 

Jettasmom: A 'fistula' is a fistula, is a hole.  (C/F the condition ' Anal fistulas'.)  It is not a 'lump', although they may have a raised swollen area around them.  Agree that fistulas are almost always caused by auto-immune conditions; they may be genetic in origin. Sometimes they are dry, more often they ooze fluid.  You can actually get a fistula open on just about any bodily area.  But this is clearly not the 'knobby growth' described by the OP.

 

UPDATE

about 2.5 weeks after administering the anti biotic ( simplicef) the lump has disappeared completely ( and today you cannot even tell it existed). Throughout its short existence, it never pained or cause any problems for the fog movment or activity level. I personally believe its disappearance had nothing to do with the antibiotics, but it was most likely a local reaction to the vaccination suite the dog was given on 9/27 .

Could well be, K9L1 - a small number of people report odd reactions to vaccines all the time. All one can say in this case is "Thank heavens for that !" - really glad for you that it seems to have cleared up without turning out to be anything nasty and consuming of time & money !