[A case of transethmoidal meningocele showing increased activity of 99mTcHM-PAO at seizure attack].

A case of transethmoidal meningocele presenting seizure attack is reported. A 59-year-old man was admitted to our hospital because of seizure attack. On admission, he was neurologically free without right olfactory dysfunction. T2-weighted image of MRI showed high intensity signal area in right frontal base, and this signal increase herniated into the ethmoidal sinus. Then 3 DCT image clearly showed right frontal base bony defect. After admission, we compared brain activity in this patient during a seizure attack and resting state using SPECT. And we found increased activity in right frontal base using 99mTc HM-PAO. So it was suspected that indicated the focus of the seizure. During the operation a unilateral bony defect and hypoplastic olfactory nerve were observed, but there was no herniated brain tissue. The association of seizure with frontobasal meningoencephalocele is reported only two cases. In one of two cases, it is presumed that reactive gliosis was epileptogenesis. On the other hand, the relationship of the temporal meningoencephalocele to the genesis of temporal lobe seizure is suggested by the extension of gliosis to the amygdalohippocampal lesion. In our case, it is possible that reactive gliosis or scar of the cyst wall may be the focus of seizure. In terms of diagnosis, 3 DCT is useful to identify the bony defect. It makes easy to diagnose the front-basal encephaloceles.