Idiopathic hypertrophic spinal pachymeningitis: report of two cases with typical MR imaging findings

SUMMARY: Two patients with a chronic progressive myelopathy were successfully surgically treated and idiopathic hypertrophic spinal pachymeningitis (IHSP) was found on histology. In both patients, an extensive extramedullary mass of low T2 signal with peripheral contrast enhancement was compressing the spinal cord on MR imaging. This imaging appearance in patients with chronic progressive myelopathy should suggest the diagnosis of IHSP.