Necrobiotic Xanthogranuloma

Necrobiotic xanthogranuloma (NXG) is a rare, chronic form of non-Langerhans histiocytosis usually found in older adults. Xanthogranulomas are lesions made of immune cells known as a histiocytes. The term necrobiotic refers to the buildup of broken down collagen fibers that can be seen under a microscope. The typical lesion is a yellow, thickened, or raised lesion (plaque) located around the eyes. In most cases the lesions are associated with conditions in which abnormal proteins are found in the blood (monoclonal gammopathies). NXG is also sometimes associated with blood cancers or lymphoproliferative disorders. As these blood disorders may arise years after the first NXG lesions appear, lifelong follow-up may be recommended. Approximately 50% of people with NXG have problems with their eyes, such as burning or itching, blurred vision, double vision, bulging of the eyeball, drooping of the eyelid, and restricted eye movement. In most cases, other parts of the body, such as the trunk, legs, face, and arms, are also involved. Internal organs may sometimes be affected. Treatment of NXG can be challenging, but is usually necessary to minimize the risk of skin ulcers and scarring. First-line therapy may include drugs used to treat cancer (such as chlorambucil and melphalan). Additional treatment options include corticosteroids, intravenous immunoglobulin, lenalidomide, interferon, radiation therapy, and surgery. In some cases, the symptoms of NXG may return after treatment. If NXG is associated with a blood cancer or a lymphoproliferative disorder, treatment focuses on the blood disorder.