Why does he have lumps all over his body

Gunnar started having lumps all over his body, his skin was like rubber, brand new vet at hospital ran all kinds of tests, all she was concerned with he wasn't getting enough veggies in his diet. Put him on two antibiotics and the poor thing lost all his fur. Went back 2 weeks later to our reg vet and he ran more tests, put Gunnar on Prednisone. This took away his lumps. Started weening him off and the lumps are back threefold. We don't know what else to do. Any help would be appreciated. The breeder said hers had them to her vet called them fatty tumors. Gunnar has at least 30 of them. Please help.

[Aleda M Cheng, D.V.M., C.V.A]

Were biopsy's performed on the lumps?  

If prednisone cured the problem even though only temporarily then the lumps are not fatty tumors.  An elevated calcium level can be indicative of cancer,  but cancer is not the only cause of elevated calcium levels.  I don't mean to make this sound like a conundrum, but some dermal cancers do respond to Prednisone.  Cellulitis, hives, and other dermal allergies and atopic conditions also respond to prednisone.  

Please have some of the lumps biopsied if this has not already been done.  If this has already been done and found to be indeterminate than it may be necessary to consult a veterinary dermatologist at a speciality referral hospital.  Please ask your vet for a referral.