This study on using steroid to reduce them looks promising. (For those with dogs with lipomas that are in hard to remove places). Most of those not completely regressed still reduced significantly.)
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0050234
Results
A total of 15 lipomas (9 subcutaneous, 3 subfascial, 2 intermuscular, 1 infiltrative) in 15 dogs (9 mixed, 6 purebred dogs, mean age 8 year, 4 male, 11 female) were injected with 0.5 mL (10 cases) or 1 mL (5 cases) of triamcinolone acetonide (Tab 1).
For all cases, diagnoses of lipomas originally identified by clinical evaluation and ultrasound were confirmed by cytological examination; lipomas showed histological evidence of normal adipocities on a proteinaceous, bluish background, and, in some cases, aggregated around a blood vessel.
After one injection, nine lipomas (six subcutaneous and three subfascial) regressed completely by 6 months follow up. Before the steroid injection, the above-mentioned lipomas showed the following ultrasound features: a hyperechoic capsule, a poorly vascularised hypoechoic or isoechoic echotexture (1 case) with thin hyperechoic stripes homogeneously distributed throughout (fig. 1).<<