Scleromyxedema with an interstitial granulomatous-like pattern: a rare histologic variant mimicking granuloma annulare.

Scleromyxedema is the generalized and sclerodermoid form of lichen myxedematosus. Its typical histological features include a diffuse deposition of mucin in the papillary and mid reticular dermis, an increased of collagen deposition, and a proliferation of irregularly arranged fibroblasts. We describe a 76-year-old man presenting with scleromyxedema associated with IgGlambda monoclonal gammopathy whose biopsy showed histological features of an interstitial granulomatous-like process consistent with interstitial granuloma annulare. The significance of these unusual granulomatous findings in the setting of scleromyxedema are unknown and have been described only once in the literature. This observation expands the spectrum of scleromyxedema and highlights the difficulty in diagnosing this disabling condition.