Linear granuloma annulare.

Granuloma annulare is a benign dermatosis with multiple clinical presentations and a common histologic picture, which is characterized by areas of degenerated collagen surrounded by palisading histiocytes. A case of granuloma annulare that presented as progressive, asymptomatic, symmetric truncal bands is described. The varied clinical presentations and possible pathogenetic mechanisms of granuloma annulare are reviewed.