Idiopathic hypertrophic pachymeningitis: A report of two patients and review of the literature

Purpose: We report the treatment and follow-up, including MRI, of two patie nts with idiopathic hypertrophic pachymeningitis and review the English lan guage literature, with emphasis on management and outcome in this rare diso rder. Methods and Materials: The files of two patients were reviewed, with relevant histopathology and imaging (MRI). The first patient has been follo wed for sixteen years (the longest MRI-documented postoperative course repo rted for this condition) and the second for two years. The English language literature was reviewed, including a summary of all reported patients that have been followed with MRI or CT imaging. Results: Despite extensive inve stigation, no underlying etiology was determined in either patient. Histopa thological studies revealed a chronic inflammatory dural infiltrate in both patients, with granulomas in the first but not the second patient. The fir st patient underwent surgery twice and has remained stable for sixteen year s, despite persistent neurologic deficits. The second patient was managed w ith dexamethasone after a surgical biopsy, and experienced complete resolut ion of all neurological deficits and abnormalities seen with MRI, Conclusio ns: Although prompt and extensive surgery has been recommended for this con dition, the results from our second patient indicate that complete remissio n can be achieved in some patients with biopsy and steroid therapy. This al so supports the view that autoimmune mechanisms underlie idiopathic hypertr ophic pachymeningitis. The first patient illustrates that extensive laminec tomies may be an effective therapeutic option but chronic discomfort may re sult. If extensive surgery must be performed, laminoplasty should be done b ecause of the potential for reduced pain and improved long-term spinal stab ility.