The diagnosis of antineutrophil cytoplasmic autoantibody‐associated vasculitis in first‐episode strokes is particularly challenging, especially in patients lacking features of systemic vasculitis. We present the case of a 71‐year‐old woman with positive myeloperoxidase antineutrophil cytoplasmic antibodies and negative proteinase 3 autoantibodies. The patient presented with 1 week history of pyramidal weakness in both upper and lower limbs, hyperreflexia, and clonus. Magnetic resonance imaging of the brain demonstrated widespread bihemispheric cortical and deep white matter acute infarcts, which are consistent with features of stroke secondary to vasculitis. Myeloperoxidase antineutrophilic cytoplasmic autoantibody‐positive vasculitis diseases are more commonly associated with renal, pulmonary, and cutaneous manifestations; however, in our patient, the central nervous system features predominated. This case highlights the challenges of diagnosing primary central nervous system vasculitis, in this case, an atypical myeloperoxidase antineutrophilic cytoplasmic autoantibody‐positive disease without the classical disease course and clinical signs.

in a study of 100 neuromuscular patients with elevated VGCC antibodies, only 6 patients were diagnosed with LEMS. This case illustrates the importance of applying appropriate clinical judgement with results of investigations.