My Dog Has A Lump Of Fatty Tissue Under His Skin, Near His Belly, What Could It Be?

Any new mass needs to be examined by a veterinarian and at least a fine needle aspirate needs to be performed.  With a fine needle aspirate a small needle is inserted into the mass to gain a cell sample.  The cells are looked at under a microscope to determine if it is benign or malignant.
Lipomas, benign fatty tumors, are very common in dogs especially labs and lab mixes.  
Malignant masses need to be removed.  Benign masses should be removed at the next anesthetic event for your dog.  Preventative care is always best--it is easier to remove a small benign mass than wait until it is larger and causing a problem.

My vet, told me that as dogs age they get these fatty cysts. I would show it to your vet, and if he says it is o.k., and it is not bothering your dog...relax.

Dog has a lump on belly vet said its ok as the lump is soft since recent visit its got bigger is this dangerous

It is his belly button because it is a puppy it will come off soon

Ask the vet

It is most likely a cyst, and you can have it drained or removed at the vets office, hope this helps, good luck to you.

Take him to the vets if you are worried but my old dog had something similar just behind her front leg and I didn't cause her pain and the vet said it was nothing to worry about and it was just there, don't worry to much until you go to the vets, hope it turns out well for you and your dog.