[A case of adult onset subacute sclerosing panencephalitis; sequential clinico-radiological findings over two years].

We present a very rare case of adult onset subacute sclerosing panencephalitis (SSPE), and explain the characteristic sequential clinico-radiological findings. The patient, a twenty three-year-old man, had noticed unsteadiness in walking about two months previously. Although inosine pranobex and intrathecal interferon were administered, symptoms worsened insidiously and he became bedridden after four months. The levels of serum and CSF anti-measles IgG antibodies have not changed. Initially, supratentorial cortical atrophy was observed, especially of the left temporal lobe, but there were no other MRI signal alterations at the time. After three months, the supratentorial cortices produced low-signal intensities in T1-weighted images and in T2-weighted MRI, the cortical margin was very unclear and white matter signal intensities had become higher. Furthermore, cortices became thinner and ventricular size increased, especially for the lateral and third ventricles. SPECT examinations showed a marked reduction in cerebral blood flow and the perfusion deficits observed seemed to be closely correlated with the abnormal MRI signal patterns. Pathological examinations of biopsy samples revealed infiltration of inflammatory cells around the small vessels. As for immunohistochemical findings, CD68 positive cells were frequently observed, and this result implied the activation of microglia. Further studies are necessary to elucidate the pathogenic mechanisms of SSPE.