"Idiopathic" cranial hypertrophic pachymeningitis responsive to antituberculous therapy: case report

We present a case similar to previously described cases of idiopathic hypertrophic cranial pachymeningitis. However, our patient responded to antituberculous therapy. This raises the possibility that some cases of "idiopathic" hypertrophic cranial pachymeningitis may represent occult tuberculous disease. A 55-year-old woman presented with a right fourth nerve palsy and a 5-month history of headaches. Magnetic resonance imaging with gadolinium revealed thick enhancing dura on the right half of the tentorium cerebelli, with edema of the adjacent midbrain, pons, and cerebral peduncle. Open biopsy of the tentorial lesion revealed only dense fibrosis with histiocytic infiltration. An exhaustive search failed to demonstrate an underlying cause. In particular, mycobacterial stains/cultures were negative, there was no granuloma formation, and the chest x-ray was unremarkable. However, because of a strongly positive purified protein-derivative skin test and residence in an area endemic for tuberculosis, the patient was placed on antituberculous medications. The patient's symptoms and signs resolved with antituberculous therapy. Resolution of the tentorial lesion was confirmed by gadolinium-enhanced magnetic resonance imaging. We conclude that this case represented occult tuberculous disease. An empiric trial of antituberculous therapy may be warranted in other cases of apparently idiopathic hypertrophic cranial pachymeningitis.