Necrobiotic Xanthogranuloma.

Objective: To identify correlations between clinical presentation, specific histopathologic findings, and subsequent disease course in patients with necrobiotic xanthogranuloma (NXG). Design: Retrospective review of medical records and histopathologic examination of fixed tissue samples. Setting: Tertiary care medical center. Patients: Seventeen patients with a diagnosis of NXG established between January 1, 1994, and December 31, 2007. Main Outcome Measures: Description and distribution of clinical lesions, presence of monoclonal gammopathy, multiple myeloma, and correlation with microscopic patterns of skin lesions. Results:: Eleven patients (65%) showed involvement of the periorbital area, and the trunk was affected in 8 patients (47%). Twelve patients (71%) had a monoclonal gammopathy; of these, 3 (18%) had multiple myeloma. Histopathologic examination of 12 patients showed findings consistent with NXG, including a band like pattern of necrobiotic granulomatous inflammation, atypical giant cells, cholesterol clefts, and plasma cells. No correlations were identified between clinical presentation and specific histopathologic findings. Although most patients had a serum monoclonal gammopathy, staining with antibodies to CD3, CD20, k light chains, and k light chains showed polytypic lymphocytes and plasma cells in all cases. Conclusions: The association between NXG and paraproteinemia is well documented and corroborated by this study. However, the skin lesions in NXG represent reactive inflammation and are not associated with the presence of monoclonal plasma cells or multiple myeloma. [ABSTRACT FROM AUTHOR]