Insulin-Induced Lipohypertrophy

A 55-year-old man with a 31-year history of type 1 diabetes mellitus presented for a routine clinical evaluation, his first in two decades. His insulin regimen consisted of a combination of neutral protamine Hagedorn (NPH) and rapid-acting insulin. In the many years since his diabetes diagnosis, he had habitually injected insulin into two locations in the periumbilical region. Two discrete subcutaneous masses were palpated. Both masses were firm and pendulous. A clinical diagnosis of insulin-induced lipohypertrophy was made. This condition has been documented with many insulin preparations. Careful attention should be paid to the teaching of correct methods of insulin . . .