Mondo Description Idiopathic hypertrophic pachymeningitis (IHP) is a rare disorder causing inflammation and thickening of the outer layer (dura) of the brain and/or spinal cord. IHP can be widespread or cause tumor-like lesions. Before IHP can be diagnosed, other conditions including sarcoidosis, tumors, meningioma, infections (syphilis, tuberculosis, and Lyme disease), and autoimmune diseases (rheumatoid arthritis, Sjogrenbs syndrome, Wegenerbs granulomatosis, and IgG4-related disease) must be ruled out. IHP often presents with headache and cranial nerve impairment. Treatment may involve prednisone and/or an immune suppressing drug. This treatment often improves symptoms, however complete recovery is rare. Surgery may be recommended for people with advanced or severe IHP. Some people with IHP have no symptoms and may not need treatment.