These two sites give some information about lipomas:http://vetmedicine.about.com/cs/dogdise ... ipomas.htmhttp://www.vetinfo.com/types-lumps-dogs.html
I've read that turmeric (which contains curcuma) has been usefully used in dogs with all sorts of tumours. But check with your own vet. In humans, curcumin isn't always absorbed very efficiently. One way to increase absorption is to take it with black pepper. But I don't know if black pepper is suitable for dogs. I've seen it mentioned in some studies on Pubmed but only one used it internally, and that was only an extract used for arthritis. Not successfully, either. One used it as a paste for acceleration of wound healing.
One Chinese herb recommended by holistic vets is Chi-Ko/Curcuma, along with L-carnitine and chromium picolinate to work on fat metabolism. In addition, turmeric is also recommended by vets to decrease the growth of lipomas.http://www.suite101.com/content/best-wa ... as-a179930
Another form of treatment is the injection of 30% calcium chloride (CaCl2) directly into small subcutaneous tumors (i.e., lipomas with a diameter of < 4 cm).3 Caution should be used to prevent overdosage with calcium salts or seepage of the calcium chloride solution into extralesional subcutaneous sites that may result in sloughing of the skin.3 The injection of 30% CaCl2 results in adipocyte necrosis, which induces acute inflammation. 3 Inflammatory cells are probably responsible for the removal of dead tissue debris.3** http://www.vet.uga.edu/VPP/clerk/Nation/index.php
**Reference 3: Kramek BA, Spackman CJ, Hayden DW: Infiltrative lipoma in three dogs. J Am Vet Med Assoc 186:81-82, 1985.
Cat's Claw: This herb is well known for its anti-tumor properties. It benefits the natural and acquired immune systems and enhances the protective power of B- and T-cells. http://www.natural-dog-health-remedies. ... -dogs.html
Again, no idea if Cat's Claw is safe for dogs.
If the immune system has anything to do with it, keeping him stress free will help. And lots of cuddles won't go amiss.