Unusual normolipidemic cutaneous xanthomatosis: a comparison of two cases illustrating the differential diagnosis.

A patient who developed diffuse normolipidemic plane xanthomas also presented with IgG lambda monoclonal gammopathy, hypernephroma, an unusual family cluster of leukemia (with two family members in two generations), and a unique, acquired C1-esterase inhibitor deficiency. A second patient presented with widespread normolipidemic papular xanthomas in which histiocytes containing Langerhans' granules were found. The lipid composition of the lesions of these two patients showed striking differences. Excesses of triglycerides and cholesterol ester were demonstated in plane xanthoma, whereas phospholipids were prominent in the popular xanthoma of histiocytosis X. We present and classify these two cases to emphasize the diagnostic value of chemical and ultrastructural studies of normolipidemic cutaneous xanthomatosis.