Necrobiotic xanthogranuloma: a 30-year single-center experience.

To characterize the clinical features, associated disorders, and treatment of necrobiotic xanthogranuloma (NXG), a rare non-Langerhans cell histiocytosis, we conducted a retrospective review of pathologically confirmed NXG at Mayo Clinic Arizona from 1987 to June 2017. Data on clinical findings, laboratory findings, associated disorders, therapy, and response to therapy were extracted. Nineteen patients were identified. Mean age was 54 years (range, 17-84) with equal gender distribution. Median follow-up was 5.5 years (range, 1-18). Most patients had a detectable monoclonal protein (84%), and IgG kappa constituted 58%. The most common cutaneous lesions involved the periorbital region (53%). The majority of patients had extracutaneous manifestations, most commonly affecting the liver (32%) and the sinuses (21%). Hematologic malignancies were diagnosed in 26% of patients and included Hodgkin lymphoma, chronic lymphocytic leukemia (CLL), smoldering myeloma, and multiple myeloma. The most common treatment was chlorambucil with or without systemic corticosteroids. Response was seen in most patients (95%), and most patients received 1-3 lines of therapy (74%). NXG is a reactive histiocytic disorder that commonly involves multiple organ systems and requires a high degree of clinical suspicion for accurate diagnosis. Treatment decisions should be based on coexisting conditions and pattern of disease involvement.