[An autopsy case of corticobasal degeneration clinically misdiagnosed as Pick's disease].

We report a 69-year-old woman who was clinically diagnosed as having a frontal lobe-type of Pick's disease. The initial symptoms were personality changes and problematic behaviors. The patient showed intellectual decline, "stehende Redensarten" and abnormal attitude in interpersonal situations such as inattentiveness and indifference in the course of the disease. Brain CT revealed a marked atrophy of the frontal lobes. In the terminal stage the patient had severe dementia, mutism, parkinsonism and cervical dystonia. Neuropathologically, there was a marked atrophy of the frontal lobes. The superior frontal gyrus was most severely atrophic. Histological study revealed mild to moderate loss of neurons, hyperplasia of protoplasmic astrocytes and many balooned neurons in the deep layers of the atrophied cerebral cortex. Severe neuronal loss was even seen only in a part of the superior frontal gyrus. The cerebral white manner showed marked diffuse fibrillary gliosis. There was neuronal loss with gliosis in the thalamus, lentiform nucleus, subthalamic nucleus, substantia nigra and inferior olivary nucleus. Marked gliosis was seen in the midbrain and pontine tegmentum. Sections from several levels of the spinal cord also showed marked gliosis of the gray matter. Antibodies against human tau stained massive argyrophilic thread-like structures and oligodendroglial microtubular masses in the affected lesions. Neurofibrillary tangles were localized in the hippocampus and parahippocampal region. Neither Pick's body nor senile plaque were observed. Corticobasal degeneration (CBD) is a neurodegenerative disease initially presenting with unilateral motor disturbances. Typical initial symptoms are rigidity, akinesia and apraxia of an affected arm. The clinical phenotype might depend upon the affected areas of the cerebral cortex. Our patient initially exhibited personality changes and was clinically diagnosed as having Pick's disease. Although our case had unusual distribution pattern of the cerebral atrophy, it was pathologically diagnosed as CBD. The review of the literature suggests the presence of clinical varieties in CBD.