Cutaneous amyloidosis in patients with progressive systemic sclerosis.

It is rarely reported that amyloidosis occurs as a complication of progressive systematic sclerosis (PSS), in comparison with rheumatoid arthritis (RA). We observed pigmentation on the upper back of six of sixty-six patients with PSS (9 percent), and recognized amyloid deposits in the skin on histochemical and electron microscopic examinations. These amyloid deposits were localized cutaneous type, according to results of morphologic and immunologic studies. Patients' levels of serum amyloid A were normal or moderately elevated. Two of the six patients had Barnett type I disease and four had Barnett type II; none had severe visceral involvement with PSS.