Xanthoma disseminatum. Report of a case, with histological and ultrastructural studies of skin lesions.

A patient with xanthoma disseminatum with typical xanthomatous lesions on the flexural surfaces and diabetes insipidus controllable by 1.5 gm daily administration of clofibrate was examined. Acid orcein and Giemsa stain of biopsy material revealed dark brown masses within the cytoplasm of histiocytes or giant cells, which were demonstrated to be elastic fibers engulfed by the tissue macrophages on electron microscopy. Numerous phagosomes, vacuoles, and concentric lamellar structures were present in the cytoplasm of the tissue macrophages. Collagen fibers were also altered in the lesion. Occasional crystals suggesting cholesterol were also found. However, no Langerhans' cell granules were found within any dermal macrophages; this indicated that these histiocytes or macrophages were different from those in histiocytosis X. It was suggested that autophagocytosis of tissue components is one of the pathologic features in the cutaneous lesion of xanthoma disseminatum.