Granuloma annulare: An elastic tissue disease? Case report and literature review

Granuloma annulare (GA) is a condition characterized by the presence of pal isading granulomas usually in the dermis. Traditionally, the histopathologi cal changes are described as consisting of focal degeneration of dermal col lagen fibers. However, no convincing evidence for such alteration is found in the literature. A histopathological study was done to ascertain the natu re of the dermal abnormality. Ten skin biopsies showing lesions of GA were studied by light and electron microscopy. On light microscopy, all lesions showed focal dermal degeneration with near total loss of elastic fibers. Ul trastructural examination in nine cases demonstrated degenerated elastic fi bers with loss of peripheral microfibrils and abnormal elastic matrix. The degenerated elastic fibers were surrounded by intact collagen fibers. These findings show that the main alteration in GA is elastic fiber degeneration and strongly suggest that the primary target leading to the development of this disorder is injury to the elastic tissue.