Synthesis of glycosaminoglycans and collagen in skin fibroblasts cultured from a patient with lichen myxedematosus

Type I and type III collagens in cutaneous mucinosis

Cutaneous mucinoses are a heterogeneous group of diseases characterized by the focal or diffuse dermal deposition of glycosaminoglycans. The histopathologic examination of many cutaneous mucinoses reveals that the collagen fibers are fragmented. We wanted to characterize the type I (COL1) and type III (COL3) collagen distribution in skin biopsy specimens of patients with cutaneous mucinosis. The diagnosis of mucinosis was based on a modification of the classification by Rongioletti and Rebora: four patients had familial papulonodular mucinosis: four had papular mucinosis, one of which was associated with myxedema and one had scleromyxedema; and one had focal mucinosis. We performed anti-type I and type III collagens immunolabeling on frozen sections. Immunofluorescence for COL1 was increased in the superficial dermis of 2/4 familial papulonodular mucinosis, in 5/5 of papular mucinosis, and in scleromyxedema and focal mucinosis cases. The mid-dermis showed intense staining for COL1 at the periphery of collagen bundles and, in three cases of familial papulonodular mucinosis and two cases of papular mucinosis, a lacy appearance. The superficial dermis of familial papulonodular mucinosis specimens and of papular mucinosis + myxedema, scleromyxedema, and focal mucinosis specimens had decreased COL3 staining. The mid-dermis showed a more prominent fibrillar staining at the periphery of the collagen bundles, and two cases of papular mucinosis showed intense labeling for COL3. Both COL1 and COL3 distributions are altered in cutaneous mucinosis. An intense labeling with COL1 is predominantly found in the superficial layer of cutaneous mucinosis. Cases of FTP revealed decreased COL3 reactivity at the superficial layer.

Ultrastructural signs of altered intracellular metabolism in acral persistent papular mucinosis

An asymptomatic 24-year-old woman presented with multiple discrete papules on the extensor surfaces of the hands and wrists. Light microscopy revealed focal increase in the amount of dermal fibroblasts as well as deposition of hyaluronidase-labile mucoid substance. The collagen and elastin were decreased. The changes were consistent with acral persistent papular mucinosis (APPM). In electron microscopy, the intercellular glycosaminoglycans showed small ruthenium red-positive granules and thin filaments indicating normal morphology. The fibroblastic cells, however, were conspicuously altered. Endoplasmic reticulum was dilated, cytoplasm contained large amounts of osmiophilic, concentric lysosomal structures, and there was distinct fibrous lamina in the nuclear membrane. It was concluded that the primary event in APPM probably affects the intracellular metabolism of the dermal fibroblast. The accumulation of lysosomal structures may be a distinct feature of APPM differentiating it from the other reactive cutaneous mucinoses, or it may only reflect nonspecific degeneration in a long-standing lesion.

Cutaneous mucinous deposits

A survey of conditions with mucinous deposits is given. The most important factors for their diagnosis are to consider these disorders and to stain the slides for proteoglycans or glycosaminoglycans; the most common routine techniques are the Giemsa and the Alcian-blue stain. More sophisticated methods allow differentiation between specific compounds, especially hyaluronic acid and various proteoglycans.