Abstract: Objective To elucidate the clinicopathological characteristic,differential diagnosis,treatment and prognosis of systemic amyloidosis.Methods An inpatient diagnosed as systemic amyloidosis was analyzed for clinical and pathological features as well as laboratory findings.The related literature was reviewed.Results The patient was confirmed to have amyloidosis of the muscle.Muscle involvement was the most prominent and first manifestation,and the patient had widespread visceral involvements,which included cardiovascular system,kidney,respiratory as well as gastrointestinal tracts and tongue.The biopsy of the muscle,mucosa of stomach and intestine,and cutaneous tissue revealed amyloid material deposited in the skeletal and smooth muscle as well as vessel walls.Conclusion Amyloid myopathy is a rare manifestation in systemic amyloidosis.Skeletal muscle weakness and stiffening may be an important clue to the diagnosis of systemic amyloidosis.

Key words: Amyloidosis, Muscular diseases