Necrobiotic xanthogranuloma: a case without paraproteinemia but with transepithelial elimination.

We report a female patient, now aged 60, followed for 20 years for lesions originally diagnosed as necrobiosis lipoidica diabeticorum. In fact, the anatomical and clinical features of her disorder correspond to the new entity described as necrobiotic xanthogranuloma. Two elements distinguish this from earlier cases: 1) two examinations failed to reveal paraproteinemia; 2) there was transepithelial elimination of cholesterol crystals and degenerated xanthomatous cell debris via hair follicles. This demonstrates the characteristic histology of the disorder and indicates that the diagnosis of necrobiotic xanthogranuloma should be considered even in the absence of paraproteinemia.