Subcutaneous Lipomas at Sites of Insulin Injection: Report of a Case

A thirty-eight-year-old female diabetic is described who bears symmetrical lipomas at the sites of insulin injection, which have persisted for twenty-six years. Incubation of biopsy specimens of adipose tissue from one of the lipomas compared with that of adjacent normal subcutaneous adipose tissue revealed an increase in baseline rates of oxidation of both glucose-1 and glucose-6-C-14 to C-14-0₂ by the lipoma tissue, as well as greater incorporation of C-14 into fatty acids. These parameters were not influenced by added insulin in the normal tissue, but were greatly stimulated in lipoma tissue. The lipoma tissue was clearly converting labeled glucose to fatty acid more efficiently than the normal tissue.