Patch-Type Granuloma Annulare with Clinical and Histological Features of Morphea: A True Overlap?

A 67-year-old woman was evaluated for a worsening asymptomatic rash located on her torso, back, and legs. She denied any chills or fevers, and reported feeling otherwise well. Clinically, large brownish, slightly atrophic plaques were seen on the torso suggestive of either morphea or a granulomatous condition. Histopathologic examination revealed an increase in interstitial histiocytes infiltrating between altered collagen fibers, palisaded granulomas with increased mucin, suggestive of granuloma annulare (GA), as well as dermal sclerosis, perineural infiltrates with plasma cells and diminished CD34 counts, that are more typical for localized scleroderma/morphea. Morphea and patch-type GA may be indistinguishable clinically and share some histopathological features. This case demonstrates similarities between these conditions and features of both conditions in the same patient.