[A case of hypertrophic pachymeningitis as a systemic autoimmune/inflammatory disorder (SAID) associated with chronic myelomonocytic leukemia].

A 67-year-old woman with past medical history of chronic myelomonocytic leukemia (CMML) presented with a chief complaint of headache, diplopia, and hearing impairment in the right ear. Examination revealed impaired ocular movement in the left eye and sensorineural hearing loss in the right ear. Cerebrospinal fluid analysis showed increased cell count and protein, and MRI showed contrast enhancement of hypertrophic dura mater. Since there were no other abnormalities which would have been a cause of hypertrophic pachymeningitis, it was considered as systemic autoimmune/inflammatory disorder (SAID) associated with CMML. Treatment with steroid, cyclophosphamide, and methotrexate led to improvement of the symptoms. SAIDs develop in up to 25% of patients with myelodysplastic syndromes (MDS) or CMML, which may be the only symptoms of MDS/CMML. As a phenotype of SAIDs, systemic vasculitis, connective tissue diseases, and neutrophilic diseases are frequently reported; however, isolated involvement of central nerve system is rarely reported. To our knowledge, this is the first report of hypertrophic pachymeningitis as SAID associated with CMML. To clarify the pathogenesis of neurologic involvement of SAIDs, accumulation of cases is necessary.