Background: Amyloidosis is an uncommon disorder characterized by deposition of insoluble pathologic amyloid fibrils in different tissues and has two main forms: systemic and localized. Primary systemic amyloidosis, as the most common type of systemic amyloidosis, is a clonal plasma cell disorder and ischemic stroke has been sporadically reported as its complication.

Case Presentation: The patient was an 88-year-old man with reduced muscle force in his right side of the body, dysarthria on the morning of admission, and a history of skin lesions. Multiple ecchymotic skin lesions all over the body especially head and neck areas along with macroglossia were observed in skin and mucous membrane examination. Neurologic examination revealed hemiplegia of the right side and reduced but symmetric deep tendon reflexes, along with drowsiness and global aphasia. In brain computed tomography, extensive infarction of left cerebral hemisphere was observed and after skin biopsy, diagnosis of amyloidosis was confirmed. Due to massive infarction of one cerebral hemisphere and extensive skin lesions, the patient died ten days later.

Conclusion: Extensive ischemic stroke may occur as a complication of primary systemic amyloidosis. Therefore, in every patient presenting with extensive ecchymotic skin lesions and stroke, this differential diagnosis should be considered. Moreover, the occurrence of ischemic stroke as the complication of primary systemic amyloidosis may lead to poor prognosis.