Neuro-Sweet disease: report of the first autopsy case.

Background: Neuro-Sweet disease is a rare condition of central nervous involvement accompanied by cutaneous Sweet lesions. Neuropathological changes in neuro-Sweet disease are unknown.

Objective: To describe post-mortem findings of the first case of neuro-Sweet disease.

Results: A 44-year-old Japanese man developed recurrent episodes of cerebral and brainstem encephalitis with cutaneous Sweet lesions from the age of 34 years. His HLA typing was B54 and Cw1, and the symptoms and MRI abnormalities markedly subsided following corticosteroid therapy. Histologically, there were multiple lesions of perivascular cuffing of small venules by macrophages without vasculitis in the thalamus, temporal lobe, basal ganglia, pons, leptomeninges or ventricular ependym.

Conclusions: The core neuropathological findings were: perivascular cuffing around particularly small veins; absence of granulomatous or necrotic angitis; mainly macrophage infiltration; and the thalamus being most affected. In the present case, the diagnosis of neuro-Sweet disease was made by skin biopsy 5 years after the onset of the central neuron system symptoms. We should pay more attention to skin lesions in steroid responsive recurrent encephalitis in patients who are HLA-B54 or Cw1 positive.