LOCALIZED GRANULOMA-ANNULARE - HISTOPATHOLOGICAL AND DIRECT IMMUNOFLUORESCENCE STUDY OF EARLY LESIONS, AND THE ADJACENT NORMAL-LOOKING SKINOF ACTIVELY SPREADING LESIONS

We studied 10 biopsies of early (< 1 week) localized granuloma annular e (LGA) lesions and 10 specimens of the normal-looking skin adjacent t o actively spreading LGA lesions for signs of vasculitis, using histol ogical and direct immunofluorescent (DIF) techniques. In the early LGA lesions, the collagen fibers showed various forms of alterations, wit h hyalinization and fragmentation being the most common; in half of th ese lesions, neutrophils and nuclear fragments in various numbers and densities were found among the altered collagen fibers. Some of the sm all blood vessels in the areas of granulomatous inflammation showed en dothelial cell hypertrophy in four cases, and in one case also endothe lial cell proliferation and luminal occlusion. In only one case, a sin gle small blood vessel, which was situated in the center of a palisadi ng granuloma, showed fibrinoid necrosis of its walls. The DIF study of all 20 specimens and the histological study of the 10 specimens of no rmal-looking adjacent skin did not reveal immune deposits in the vesse ls' walls, or histological evidence of vasculitis, respectively. We be lieve that these findings do not support a role of vasculitis in the f ormation of LGA lesions, but suggest that neutrophils might play a pri mary or secondary role in their pathogenesis.