Lipoid proteinosis: clinical, histologic, and ultrastructural investigations

The case of a 12-year-old boy with lipoid proteinosis is reported. Physical examination revealed long-standing varicella-like scars and areas of hyperpigmentation on the face and upper limbs with no evidence of photosensitivity, hoarseness, small papules along the free margins of eyelids, tongue firmness with short frenulum, and widespread papular lesions of the oral cavity. Histologic and ultrastructural examination revealed the characteristic skin changes: pink, hyaline-like, strongly periodic acid-Schiff-positive material in the dermis, surrounding blood vessels, and sweat glands; thin (30 to 35 nm) collagen fibrils interspersed in abundant amorphous material; blood vessels surrounded by thickened, multilayered basement membranes, in which layers of typical, homogeneous basement membrane material were alternating with electronlucent areas filled by various amounts of thin, cross-striated fibrils, arranged perpendicularly. These findings are of great interest since they show a complex relationship between type IV and type III-like collagen components.