Fig. 2.

Neuropathology of CNS TTR amyloidosis. Severe leptomeningeal and subpial TTR amyloid deposition associated with severe cerebral amyloid angiopathy with splitting of the vessel wall and double-barreling appearance in several vessels (a–e). The amyloid deposition has the characteristic green birefringence under polarized light in the Congo red staining (b and c). Despite massive amyloid deposition, this was restricted to the meningocortical penetrating vessels, with no parenchymal amyloid deposition. In f, subependymal amyloid deposition in the fourth ventricle. TTR immunohistochemistry: a, d–f Congo red staining: b and c. Scale bars—a: 500 µm; b, c, f: 200 µm; d and e: 100 µm