Lipoid proteinosis. A biochemical and ultrastructural investigation of two new cases.

Lipoid proteinosis is a rare autosomal recessive disease characterized by cutaneous and visceral lesions, in which large amounts of amorphous material are constantly found in stroma. Morphological and biochemical studies indicate abnormal collagen production, but little attention has been paid to the lipid component of lesions. Microscopic and ultrastructural studies of skin, with special emphasis on fibroblasts, vessels, nerve endings and eccrine sweat glands, were conducted in two patients with lipoid proteinosis. Biochemical studies were undertaken in cultured fibroblasts. Evidence of lysosomal storage in epithelial cells of eccrine sweat glands and in dermal histiocytes, very similar to that found in some metabolic disorders, particularly Farber disease, was found in both cases. Our findings suggest that two alterations might coexist in lipoid proteinosis, one characterized by impaired normal collagen production and the other related to a metabolic defect which may lead to accumulation of ceramide or more complex lipids.