Late-onset neuroaxonal leucoencephalopathy with spheroids and vascular amyloid.

A 54-year-old man with a 7-year history of early-onset, slowly progressive dementia and motor impairment characterised by diffuse, non-enhancing white matter signal change. Neuropathologic examination demonstrated subcortical pigmentation with neuroaxonal spheroid formation, profound axonal loss with secondary myelin degeneration and widespread betaA4 immunopositivity involving meningeal and subcortical vessels. There was relative sparing of brain stem and cerebellar white matter. The neocortex was normal. The appearances expand the spectrum of adult-onset neuroaxonal leucoencephalopathy with spheroids (NALS) and demonstrate that vascular betaA4 amyloid plays a key role in the white matter pathology of NALS.