Semantic dementiaを呈したDementia lacking distinctive histologyの1剖検例

An Autopsy Case of Dementia Lacking Distinctive Histology Showing Semantic Dementia

要旨　病初期に失語症が目立ったDementia lacking distinctive histology（DLDH）の剖検例を報告した。47歳頃，自発性低下にて発症。数カ月後にはsemantic dementiaを呈し，言語障害は超皮質性感覚失語から超皮質性混合失語へと進展した。さらに，脱抑制的行動を認め，徐々に動作緩慢，筋固縮が出現した。その後，49歳時歩行不能となり，全経過2年8カ月で死亡した。脳重1,350g。病理学的には中・下側頭回に強調される前頭・側頭葉の神経細胞脱落と海綿状態，高度な尾状核変性，黒質，視床の明らかな神経細胞脱落を認めたが，被殻，淡蒼球，扁桃核病変は軽度であった。老人斑，神経原線維変化，レビー小体，ピック球はなく，Gallyas，タウ染色でも異常は認めなかった。さらに，海馬歯状回などにユビキチン陽性神経細胞内封入体もみられないことからDLDHと診断した。本症例は，本邦最初のDLDHの剖検例である。

We report an autopsy case of dementia lacking distinctive histology（DLDH） showing semantic dementia. At age 47, a Japanese man developed aspontaneity, followed by semantic dementia a few months after the onset. Thereafter he developed disinhibition and the language disturbance, which progressed transcortical sensory aphasia and terminally mixed transcortical aphasia. At age 48, about 10 months after the disease onset,neurological examination revealed frontal signs and hyperreflexia in the four extremities and 4 months later, the patient presented with mild rigidity in the right upper and lower extremities. At age 49, 1 year and 8 months after the onset of the disease, he could not walk by himself. At age 50, 2 years and 8 months after the onset, he died of pneumonia. The brain weighed 1,350g. Macroscopically, atrophy of the frontal lobes and temporal lobes, predominant in the left, was evident. The caudate nucleus was severely atrophic, in addition to the depigmentation of the substantia nigra. Neuronal loss and astrocytosis was obvious in the cerebral cortex, prominently in the frontotemporal lobes, amygdala, caudate nucleus, putamen, pallidum, thalamus, and substantia nigra. In the caudate nucleus, prominent neuronal loss with fibrillary gliosis was obvious. Senile plaques, neurofibrillary tangles, Pick bodies, astrocytic plaques, and tufted astrocytes were not found by Gallyas and tau staining. Ubiquitin-immunoreactive intracytoplasmic inclusions were not encountered in the hippocampal dentate gyrus and superficial layers in the frontotemporal cortex. On the basis of meticulous perusal of the literature, we believe that our case is the first autopsy case of DLDH reported in Japan.

（Received : November 16, 2004）