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.