Subcutaneous xanthogranulomatosis: an inflammatory non-X histiocytic syndrome (subcutaneous xanthomatosis).

The histopathologic features in four cases of subcutaneous xanthogranuloma were reviewed. All patients were elderly men and no associated diseases or hyperlipidemia were present. The microscopic picture was uniform in seven biopsy specimens: foam cells and masses circumscribed by Touton cells replacing the adipose tissue. Most cells, including foam cells, showed a positive reaction for the macrophage marker MAC387. Diffuse, sparse T cells and focal perivascular B cell nodules were identified. Electron microscopic examination showed histiocytes and lysosome-rich cells with myelin bodies. All patients are alive and well. We believe that we have identified a form of adult subcutaneous xanthogranuloma syndrome that can be initially confusing and lead to overdiagnosis and overtreatment.