A 76-year-old man was admitted to our hospital presenting with fever, redness and pain in both the periocular regions, and disturbance of consciousness. He had neck stiffness, and cerebrospinal fluid analysis suggested aseptic meningoencephalitis. Laboratory tests showed increased levels of C-reactive protein, soluble IL-2 receptor (sIL-2R) and MPO-ANCA. Magnetic resonance imaging revealed hyperplastic bone marrow in the clivus and cervical vertebra. Although T-cell receptor gene rearrangement was detected in the bone marrow blood, bone marrow biopsy of the ilium showed no malignant findings. Then he experienced bilateral auricular inflammation and painful erythema of the ankle. A leg skin biopsy demonstrated neutrophilic infiltration into the dermis with no signs of vasculitis. His HLA-type was defined as Cw1. He was subsequently diagnosed with neuro-Sweet disease. Intravenous administration of methylprednisolone (1,000 mg/day) for 5 days and subsequent oral intake of prednisolone (60 mg/day) improved his symptoms. When the prednisolone dose was reduced to 30 mg/day, his symptoms returned and a new lesion was detected in the splenium of the corpus callosum. Upon additional treatment with cyclosporine, the prednisolone dose could be reduced without symptom relapse; sIL-2R and MPO-ANCA levels also decreased to normal. The present case suggested that the activity of neuro-Sweet disease may be associated with myeloid hyperplasia, T-cell receptor gene rearrangement and the amounts of soluble interleukin-2 receptor and MPO-ANCA.