Abstract
We report a case of idiopathic brain stone occurring in the right frontal lobe. A 49-year-old man was transferred to our department for post-ictal drowsiness. He had 40 year history of generalized convulsion and slight mental deficiency. Head CT scan revealed, without enhancement effect, a dense bony mass in the right frontal lobe. MRI clearly showed the shape, heterogeneous composition and the anatomical relation to the surrounding structures of the mass. Only an avascular huge mass was observed on the 3D-helical CT scan and cerebral angiography. The mass lesion was removed totally through the pterional approach. The postoperative course was uneventful and anticonvulsants could be reduced with good controlled symptomatic epilesy. In the pathological findings, cystic wall was composed of fibrous connective tissue and calcification including myeloid metaplasia, and its lumen was filled with necrotic amorphous eosinophilic material. The mass was diagnosed as an idiopathic brain stone because of its unkown etiology. Because an idiopathic brain stone, especially over 5cm in diameter, is extremely rare, the etiology and clinical symptoms of this condition are briefly discussed.
