• Hashimoto’s encephalopathy; Creutzfeldt
• Jakob disease
• Hashimoto’s encephalopathy

Doherty et al have recently reported in this journal on a case of Hashimoto’s encephalopathy clinically mimicking Creutzfeldt–Jakob disease.¹ As neuropathological analysis of a brain biopsy in this case revealed spongiform change and sparse mononuclear infiltrates in perivascular spaces, the authors suggested that Hashimoto’s encephalopathy is an encephalitic process. We have previously described a necropsy case of Hashimoto’s encephalopathy showing lymphocytic vasculitis of veins and venules of the brain stem, supporting the hypothesis that vasculitis represents the morphological substrate of Hashimoto’s encephalopathy.² Doherty et al have challenged our diagnosis and stated that the term vasculitis should be reserved for lesions with inflammation and fibrinoid necrosis of arterial vessels.

Lymphocytic vasculitis is a generally accepted pathological subtype covered by reviews and standard textbooks.^3,4 It is characterised by the presence of lymphocytes within the vessel wall and is encountered in Wegener’s disease, systemic lupus erythematosus, and Behcet’s disease, to name but a few conditions.⁴ That the diagnosis is more difficult than for necrotising arteritis does not, however, imply that lymphocytic vasculitis does not exist, …