Idiopathic hypertrophic pachymeningitis: Features of 9 patients and a literature review

Abstract

Introduction: Idiopathic hypertrophic pachymeningitis (IHP) is a rare disorder presenting with headache, cranial and spinal neuropathy. This study is to explore the clinical, laboratory and imaging changes; treatment; and clinical outcomes of idiopathic hypertrophic pachymeningitis (IHP). Methods: This was a retrospective evaluation of 9 patients (5 men and 4 women; mean age: 53.6 years), their clinical features, laboratory tests, cerebral spinal fluid (CSF) analysis, MRI results, pathological features, treatment and clinical outcomes from a tertiary centre in Qingdao, North East China. The serum IgG4 was negative for all the cases. Results: Headache was the most common symptom (7/9), followed by oculomotor, trigeminal, abducens and facial nerve neuropathies, and limb numbness in one case. Two cases showed increased ESR and CRP, and four were positive for ANA or anti-SSA antibodies. On CSF analysis, 2/7 had increased pressure, and 4/7 showed lymphocytosis and high protein levels. MRI revealed a thickening and enhancement of the dura, mainly involving bilateral tentorium (85%), falx cerebri (57%), and cerebellar hemisphere (57%). The tissue biopsy of dura mater in three cases showed thickened collagen fibers, lymphocytosis and focal necrosis, with similar but not identical features to IgG4-related sclerosing disease. Most patients were treated with corticosteroids, and 79% showed improvement. The abnormal thickness and enhancement of the dura mater disappeared in one case. Conclusion: Gadolinium-enhanced MRI serves as the key preliminary investigation for the diagnosis and evaluation of the clinical course for IHP. Majority of patients have good respond to steroid.