Lipoid proteinosis of the oral mucosa: case report and review of the literature.

We describe a 37-year-old woman who presented with progressive mouth dryness. Physical examination revealed long-standing plaques on the face and upper limbs, papular lesions of the oral cavity and tongue firmness. A lower lip biopsy was performed. Light microscopy demonstrated accumulation of PAS-positive material around blood vessels, capillaries and salivary gland canaliculi as well as focally massive hyaline deposits in the submucosa. Immunohistochemistry revealed widespread presence of type IV collagen in the hyaline material and around thickened blood vessels. Laminin immunoreactivity was particularly strong at thickened basement membranes. The above findings were compatible with lipoid proteinosis, which is likely to involve primary perturbation of collagen metabolism and production of glycoproteins.