The interstitial variant of granuloma annulare: Clinicopathologic study of 69 cases with a comparison with conventional granuloma annulare.

Interstitial GA differs from the classical GA in several respects, including morphology and immunophenotype. Use of antibodies to CD163 may be helpful for distinguishing the interstitial variant from other conditions. Recognition of the interstitial variant is of importance to explain the presence of lesions that clinically are suspicious for GA but histologically do not resemble the conventional form of the disease.