[Fatty tissue necrosis and oil granuloma after subcutaneous injections of vitamin B12].

A patient is described who developed fatty tissue necrosis and oil granuloma in her thigh after repeated subcutaneous injection of vitamin B12. The injections were taken in a badly documented attempt to prevent migraine. The preparation used was vitamin B12 combined with a mineral oil to give slow release resorption. We describe the histopathological mechanism for reaction of fatty tissue to mineral oil injections. The 40 ml cavity of fat necrosis had to be drained out several times and over a long period of time before our patient was without symptoms.