[Idiopathic hypertrophic cranial pachymeningitis associated with Horner's syndrome. A case report].

A 64-year-old man was admitted to our hospital for recurrence of visual disturbance and double vision experienced 1 year previously. He was alert and oriented. Bilateral light perception in a vision test, the third to the sixth cranial nerve palsies on the left side, and neck stiffness were observed. The patient exhibited left blepharoptosis, anisocoria and a left miotic pupil. After a pupillary drug test, a diagnosis of Horner's syndrome was made. Laboratory tests revealed hypoalbuminemia, elevated erythrocyte sedimentation rate, positive rheumatoid factor, and elevated p-ANCA. Examination of the cerebrospinal fluid showed increased initial pressure and pleocytosis, but its bacterial and fungal cultures were negative. Cranial magnetic resonance imaging after intravenous administration of gadolinium revealed mild brain edema and marked hypertrophy of the left tentorium cerebelli, bilateral frontal dura and falx. Marked hypertrophy of the dura accompanied by cellular infiltration was observed in biopsied dura specimens. The patient was given a diagnosis as idiopathic hypertrophic cranial pachymeningitis (IHCP). His ocular symptoms gradually improved with methylprednisolone pulse therapy and oral prednisolone. This is the first reported case of IHCP associated with Horner's syndrome. Previous anatomical findings of the cavernous sinus suggest that Horner syndrome in this patient might be due to a mechanism other than constrictive compression of the cranial nerves by the hypertrophic dura mater.