Histopathology of Moyamoya angiopathy in a European patient.

Background And Purpose: Moyamoya angiopathy (MMA) is rare outside Asia. Little is known about pathophysiology in European patients. This study aims to elucidate the histopathology of non-Asian MMA and its similarities and differences to those cases from Asia.

Methods: Here, we present a 57-year-old European woman with MMA and describe the post-mortem examination results of the brain and cerebral arteries.

Results: Histopathological findings in cerebral blood vessels were identical to those found in Asians. This included thickening and undulation of the internal elastic lamina as well as fibrocellular thickening and proliferation of smooth muscle cells of the intima in the distal segments of the internal carotid arteries and in proximal and middle segments of the anterior and middle cerebral arteries. Collateral vessels showed fragmented internal elastic lamina and thinning of the media with isolated microaneurysms.

Conclusions: Histopathological changes found in this European patient are identical with those described in Asians. Despite suspected different genetic triggers and unknown pathophysiological cascades, MMA in Europeans seems to result in a common final pathway compared with the disease in Asians.