Papulonodular mucinosis in systemic lupus erythematosus.

A 41-year-old man with systemic and serological manifestations of systemic lupus erythematosus presented with a diffuse eruption comprising annular plaques. Histopathology revealed diffuse deposition of mucin throughout the dermis, consistent with papulonodular mucinosis. This uncommon entity of unclear pathogenesis has been described in systemic lupus erythematosus, discoid lupus erythematosus, and subacute cutaneous lupus erythematosus.