Linear morphea with secondary cutaneous mucinosis.

Secondary mucinosis is a common finding in connective tissue diseases, especially in lupus erythematosus and dermatomyositis, but is seen only rarely in morphea. We report the case of a 9-year-old boy who presented with linearly arranged, flesh-colored to erythematous, indurated, very tender plaques on his right arm. He had similar lesions on his midchest and upper back. Histopathology revealed the characteristic findings of morphea and mucin deposition between thickened collagen bundles. This is an unusual case of linear morphea with hyaluronic acid deposition.