We reviewed 32 cases of necrobiotic xanthogranuloma and 16 cases from the world literature. Necrobiotic xanthogranuloma is a destructive dermal and subcutaneous xanthogranuloma that most frequently involves the face (periorbital region) and trunk. Monoclonal gammopathy is common (IgG-kappa in 23 cases and IgG-lambda in nine cases), and cryoglobulins have also been found. Low complement levels, anemia, and leukopenia are frequently present. Bone marrow examination shows plasma cell proliferation and, rarely, true myeloma. We describe mucosal, muscle, and systemic lesions, including xanthogranulomatous myocardial lesions. The clinical course is chronic and often progressive. Low-dose chlorambucil treatment is safe and effective, but individual patients have responded to treatment with corticosteroids, melphalan, local radiation, and plasma exchange.