Necrobiotic xanthogranuloma

Necrobiotic xanthogranuloma
Synonyms	NXG
Specialty	dermatology

Alternate names

NXG

Definition

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.

Signs and symptoms

• 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

• 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.

See also

• List of cutaneous conditions