The first autopsied case of diffuse Lewy body disease (DLBD): re-examination by recent immunostaining methods

The 50th Anniversary of Japanese Society of Neuropathology

Abstract

Materials from our first autopsied case of diffuse Lewy body disease (DLBD), that was originally reported in 1976, were re-examined using recent immunohistochemical methods. Lewy pathology consisting of Lewy bodies and Lewy neurites appeared much more marked with alpha-synuclein immunostaining than had been detected with classical stainings. This case and our other similar cases prompted us to propose the terms “Lewy body disease” in 1980 and “diffuse Lewy body disease” in 1984. We also reported in 1990 that DLBD was classified into two forms: a pure form and a common form. Based on these studies the term “dementia with Lewy bodies (DLB)” was proposed in 1996. Since 1980, we have insisted that DLB, Parkinson disease (PD), and PD with dementia (PDD) should be understood within the spectrum of Lewy body disease. This insistence has been recently accepted by the International Workshop and the International Working Group on DLB and PDD in 2005 and in 2006, respectively.

INTRODUCTION

In 1976, we reported¹ the first autopsied case characterized by: (i) clinical features of progressive dementia and parkinsonism; and (ii) neuropathological findings showing both numerous cortical and brain stem Lewy bodies and Alzheimer pathology. In 1978, we also reported² the detailed morphological and histochemical features of cortical Lewy bodies, based on three similar cases, including our first case. Furthermore, we reported³ two similar German autopsied cases. This was the first case report of diffuse Lewy body disease (DLBD)⁴ not only in Germany but also in Europe. In 1984, we proposed⁴ the term DLBD based on our 11 autopsied cases. Although some similar cases have been reported in Japan since our reports, DLBD was thought to be a rare dementing illness. In fact, only Okazaki et al.⁵ and Forno et al.⁶ had reported similar cases in 1961 and 1978, respectively. Since our proposal of the term DLBD, many DLBD cases have been reported in Europe and America. Based on our DLBD studies, the new term “dementia with Lewy bodies (DLB)” was proposed at the first International Workshop in 1995.⁷ The clinical and pathological diagnostic criteria were published in Neurology in 1996.⁸ Since then, DLB has been able to be clinically diagnosed, and has been reported to be the second most frequent dementia following Alzheimer's disease (AD).

Cortical Lewy bodies had been overlooked in classical staining preparations prior to our reports.^1–4 However, recently it has become possible to easily detect cortical Lewy bodies and Lewy neurites by alpha-synuclein immunostaining.

In this paper, we re-examined our first DLBD case, using various immunohistochemical methods.

CASE REPORT

As both the clinical data and classical neuropathological findings were described in detail in our previous paper,¹ only the summary of this case is presented here.

A 56-year-old woman demonstrated mild neck tremor and forgetfulness. Dementia progressed gradually. She was admitted to a psychiatric hospital because of profound dementia and psychomotor restlessness. Thereafter, muscle rigidity and apathy also developed. She died of ileus at the age of 65 years.

The brain weighed 1130 g. Mild diffuse brain atrophy with mild hippocampal atrophy was found.

The main pathological features were as follows: (i) Lewy bodies were scattered in the substantia nigra, locus ceruleus, dorsal vagal nucleus, substantia innominata and so on (Parkinson disease [PD] pathology); (ii) the most characteristic finding was the presence of numerous palely eosinophilic round or oval inclusion bodies in small neurons at the deeper cortical layers. These cortical bodies were quite similar to brain stem Lewy bodies on both various histochemical stainings and electron microscopic findings; and (iii) numerous senile plaques and neurofibrillary tangles were found throughout the whole brain (AD pathology).

This case can be now diagnosed as having the common form⁹ (especially AD form¹⁰) of DLBD.

Recent immunohistochemical findings

We re-examined the brain of this case using alpha-synuclein, beta-amyloid, AT8 and TDP43 immunostaining preparations from archived paraffin blocks of the brain.

The most remarkable feature on alpha-synuclein immunostaining preparations was the presence of numerous Lewy bodies and Lewy neurites in the hippocampal and parahippocampal areas, other limbic areas and neocortices. In the hippocampus, many Lewy bodies were found in the CA1 and subiculum, and more marked Lewy neurites in the CA2–3 (Fig. 1). As for the cerebral cortex, Lewy neurites were highly predominant in the superficial cortical layers, and plaque-like Lewy neurites were also scattered in some neocortical cortices (Fig. 2). Lewy bodies were mainly detected in the deeper cortical layers (Fig. 3). However, fewer signs of Lewy pathology consisting of Lewy bodies and Lewy neurites were found in the pre- and post-central, transverse and visual cortices.

Figure 1. Numerous Lewy neurites in the CA2 area of the hippocampus (alpha-synuclein immunostaining).

Figure 2. Numerous Lewy neurites with plaque-like neurites in the superficial layer of the insular cortex (alpha-synuclein immunostaining).

Figure 3. Many cortical Lewy bodies in the deeper layer of the parahippocamal cortex (alpha-synuclein immunostaining).

In addition, Lewy pathology was more prominent in the amygdala (Fig. 4), and was also marked in the nucleus basalis of Meynert and claustrum. In the brain stem, the substantia nigra, locus ceruleus, reticular formation, raphe nuclei, and dorsal vagal nucleus and so on, were the predirection sites of Lewy pathology.

Figure 4. Marked Lewy bodies and Lewy neurites in the amygdala (alpha-synuclein immunostaining).

In beta-amyloid immunostained preparations, numerous senile plaques were found throughout the whole cerebral cortex. On AT8 immunostaining, numerous neurofibrillary tangles were scattered throughout the hippocampus, cerebral cortices and amygdala. On TDP43-immunostained preparations, TDP43-positive neurons were scattered throughout the hippocampus, parahippocampus and amygdala. Positive neurons were also rarely present in the limbic cortices.

DISCUSSION

At the 50th Anniversary of the Japanese Society of Neuropathology, I (KK) was requested to present our first DLBD case¹ showing progressive dementia and parkinsonism, which we had reported in Acta Neuropathologica in 1976. I had been the patient's attending physician when she was admitted to our hospital. At that time, she had already become severely demented and had marked parkinsonism. I clinically diagnosed the patient as having AD. At that time, it had been thought that both AD and Pick's disease were rare in Japan. Neuropathologically the findings were compatible with AD and PD. In addition, I found many eosinophilic inclusion bodies in small neurons of the deeper layers of the cerebral cortex. Then, I wondered what these bodies were. Prior to that time, it was thought that Lewy bodies only rarely occurred in the cerebral cortex.

Thereafter, I also found many similar cortical eosinophilic bodies in the brain of another patient² with similar clinical symptoms. I became interested in these cortical eosinophilic bodies. Morphologically these bodies were similar to, but somewhat different from, brain stem Lewy bodies. Therefore, I could not identify these cortical eosinophilic bodies as Lewy bodies. Based on histochemical and electron microscopic examinations, I demonstrated that these cortical eosinophilic bodies were cortical Lewy bodies. In 1978, we reported a second paper²“Lewy bodies in cerebral cortex” in Acta Neuropathologica, based on our three cases including the first case. In that report, the close relationship between cortical Lewy bodies and neuronal cell death was for the first time indicated by showing six developmental stages of cortical Lewy bodies. In addition, we pointed out for the first time that the amygdala and claustrum are also predilection sites for Lewy bodies. Following these papers, some similar cases were reported in Japan. In the USA, a Japanese neuropathologist, Okazaki, and his colleagues⁵ reported two similar American autopsied cases without Alzheimer pathology in 1961, but these cases had not received attention until our citation of their paper in our first paper.¹ In addition, Forno et al.⁶ also reported a similar American case in 1978. In 1979, we reported³ two similar German cases when I was at the Max-Planck Institute of Psychiatry in Munich. These were the first DLBD cases reported in Europe. In 1984, we proposed⁴ the term “diffuse Lewy body disease (DLBD)” based on our 11 autopsies including Japanese, German and Austrian cases. As we proposed it in 1980, ¹¹ DLBD was thought to be a type of “Lewy body disease”. We classified Lewy body disease into three types: brainstem type, traditional type and diffuse type. The diffuse type is now considered DLBD, while the brain stem type is considered PD. After our proposal of DLBD in 1984, this disease received more attention among European and American researchers. In 1990, I reviewed 37 autopsied DLBD cases reported in Japan.⁹ Then I classified these cases into two forms: a common form with a more or less Alzheimer pathology, and a pure form without such findings. In addition, I pointed out that the clinical features differed between the two forms. In the common form, all cases showed presenile or senile onset, and the chief clinical feature was progressive dementia, followed by parkinsonism in 70% of cases, while in the pure form most cases showed early onset and the chief clinical symptom was parkinsonism, followed by dementia. In 1993, when I was invited to the 150th Anniversary of the German Psychiatry Association, I presented the clinical differences between Japanese and Euro-American cases of DLBD¹². In the common form, there was no difference between the two, while in the pure form, Japanese cases were usually of young onset with parkinsonism as the chief symptom and Euro-American cases were of older onset with progressive dementia as the chief symptom, similar to the common form. Around that time, the term “senile dementia of Lewy body type” was proposed by Perry et al.,¹³ and the term “Lewy body variant of Alzheimer's disease by Hansen et al.¹⁴ in 1990. In 1995, the first International Workshop⁷ was held in Newcastle-upon-Tyne, UK. Then, the term “dementia with Lewy bodies” (DLB) was proposed, and the clinical and pathological diagnostic criteria (Consortium on Dementia with Lewey Bodies guidelines)⁸ were published in Neurology in 1996. In 1996, we proposed the cerebral type of Lewy body disease,¹⁵ in which progressive dementia without parkinsonism was the main symptom, and cortical Lewy bodies were marked in the cerebral cortex, but only rare Lewy bodies were present in the brain stem. The presence of the cerebral type means that Lewy bodies could occur first in the cerebral cortex and later develop in the brain stem.

As above-mentioned, we proposed the term Lewy body disease in 1980,¹¹ and since then, we have insisted that DLB(D), PD, and Parkinson's disease with dementia (PDD) should be understood within the spectrum of Lewy body disease.¹⁶ This insistence has been recently accepted by the International Workshop and the International Working Group on DLB and PDD in 2005¹⁷ and in 2006,¹⁸ respectively.

In 1997, two very important findings were reported. Polymeropoulas et al.¹⁹ reported the mutation of the alpha-synuclein gene in familial PD, and Spillantini et al.²⁰ reported alpha-synuclein in Lewy bodies. Since then, alpha-synuclein has received attention in neuropathological and molecular biological studies.

Our alpha-synuclein immunohistochemical examination of materials from the first DLBD case disclosed much more marked Lewy pathology in the cerebral cortex than we had expected. Only this Lewy pathology could explain the profound dementia in this case. In addition, this case also had both PD and AD. Therefore, the case is now diagnosed as having a common form⁹ (especially AD form¹⁰) of DLB(D).

ACKNOWLEDGEMENTS

The authors thank Mrs Chie Haga, and Dr Haruhiko Akiyama, Tokyo Institute of Pschiatry for technical assistance.