Generalized eruptive xanthoma with prominent deposition of naked chylomicrons: evidence for chylomicrons as the origin of urate-like crystals.

Eruptive xanthoma is defined by the combination of its clinical and histopathological features. While a nodular dermal infiltrate rich in foamy macrophages and associated with extracellular lipid deposition is typical of eruptive xanthoma, some microscopical variability can be seen. Herein, we report an unusual case of eruptive xanthoma exhibiting triglyceride deposition in a peculiar configuration. A biopsy from a papular lesion showed prominent deposition of crystalline material, surrounded by many foamy histiocytes, in the upper and middle dermis. Such material has been previously termed 'urate-like crystals'. An immunohistochemical analysis using antibodies to lipoprotein suggested that the substance is composed of chylomicrons. This observation suggests that naked chylomicrons may be deposited in the dermis of patients with severe hypertriglyceridemia.