Acta Neuropathol (1996) 92 : 534–539

© Springer-Verlag 1996

C A S E R E P O RT

Kenji Ikeda · Haruhiko Akiyama ·
Shuji Iritani ·Koichi Kase · Tetsuaki Arai ·
Kazuhiro Niizato · Noriomi Kuroki · Kenji Kosaka

Corticobasal degeneration with primary progressive aphasia
and accentuated cortical lesion in superior temporal gyrus:
case report and review
Received: 5 February 1996 / Revised, accepted: 13 May 1996

Abstract A 57-year-old woman showed progressive sensory aphasia as an initial symptom, and then developed
total aphasia within 6 years and, finally, severe dementia.
Neuropathologically, the cerebral cortex was most severely affected in the superior and transverse temporal
gyri, and subsequently in the inferior frontal gyrus, especially in the pars opercularis. The degeneration in the subcortical grey matter was most severe in the substantia nigra, and it was moderate to mild in the ventral part of thalamus, globus pallidus and striatum. Cytopathologically, in
addition to achromatic ballooned neurons, massive taupositive types of cytosekeletal abnormalities were observed both in neurons and glia, mainly in the degenerating region. This cytoskeletal pathology coincided with
that reported in corticobasal degeneration (CBD). On Bodian staining, only a few neurofibrillary tangles were
found in the entorhinal pre-alpha layer and substantia nigra. Pick’s bodies and senile plaques could not be found.
This case is thought to represent a type of CBD, but with
its cortical lesion focus located in the speech area instead
of the frontoparietal region. A survey of 28 pathologically
evaluated cases of CBD revealed two similar cases, both
of which began with progressive aphasia and presented
cortical degeneration in the superior temporal gyrus. An
overview of CBD cases clarified the features in another
group of cases, in which the cerebral accentuated focus
was shifted forward from the central region, clinically resembling Pick’s disease. The clinical manifestations in

CBD seem to be the expression of these diverse cortical
lesions. Primary progressive aphasia may include cases of
CBD with involvement of the language center.
Key words Corticobasal degeneration · Primary
progressive aphasia · Tau · Cytoskeletal abnormality

Introduction
Since the first report of “corticodentatonigral degeneration” by Rebeitz et al. [20], many reports of cases of this
disease entity have accumulated. In most of these cases of
corticobasal degeneration (CBD), cortical degeneration is
frequently found in the frontoparietal region, especially
around the central fissure, and this degeneration seems to
correspond to the clinical motor and/or apraxia symptoms
characteristic of this disease. Recent advances in silver
and immunohistochemical staining methods have brought
to light previously unrecognized cytopathological evidence of widespread argyrophilic and tau-positive abnormalities in both neurons and glia [5, 6, 8, 17, 18, 23, 24].
We report a case of CBD in a patient who exhibited primary progressive aphasia and CBD pathology. Together
with a survey of CBD cases focusing on the cortical lesions, the diversity of cortical foci of degenerating areas
and clinical expression of this disease are discussed.

Case report
K. Ikeda (Y) · H. Akiyama · S. Iritani · K. Kase. T. Arai ·
K. Niizato · N. Kuroki · K. Kosaka
Department of Neuropathology, Tokyo Institute of Psychiatry,
2-1-8 Kamikitazawa, Setagaya-ku, Tokyo 156, Japan
Tel.: +81-3-3304-5701 (Ext. 345); Fax: +81-3-3329-8035
K. Ikeda · S. Iritani · K. Kase · T. Arai · K. Niizato · N. Kuroki
Tokyo Metropolitan Matsuzawa Hospital,
2-1-1 Kamikitazawa, Setagayaku, Tokyo 156, Japan
K. Kosaka
Department of Psychiatriy,
Yokohama City University School of Medicine, 3-9 Fukuura,
Kanazawa-ku, Yokohama 236, Japan

The patient was a right-handed female with an unremarkable family history. At the age of 58 years, she became hard of hearing and
could not speak clearly. Her ability to understand words deteriorated progressively. At the age of 61 years, she consulted a medical
university hospital, where the disturbance of both auditory sensation and language function was pointed out. Thereafter, although
she could perform household activities and her daily habits and
personality did not change, her language ability gradually deteriorated. She could not understand spoken or written language at all,
nor could she write a letter, but she spoke meaningless phrases,
and finally she showed sensory aphasia. At 64 years of age, she
was admitted to a mental hospital because of a 1-year history of
psychomotor excitement and problematic behavior. At the time of

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Materials and methods
The brain was fixed in 10% neutral formalin. Tissue blocks were
embedded in paraffin, and sections were stained with hematoxylin
and eosin, Kluever-Barrera, Bodian, modified Gallyas-Braak (GB) [23], and Holzer methods, For immunohistochemical evaluation, paraffin sections were incubated with primary antibodies for
3 days and then incubated with the biotinylated secondary antibodies for 2 h at room temperature. Sections were then incubated
with avidin-biotinylated horseradish peroxidase complex (ABC,
Vector), followed by reaction with diaminobenzidine containing
nickel ammonium sulfate. The primary antibodies employed in
this study were: human-tau (pool 2) (1 : 50 000, rabbit polyclonal,
recognizes the amino acid sequence of 299–385 in the longest isoform of human tau [7]); C5 (1 : 1000, mouse monoclonal, recognizes phosphorylated epitope of tau at Ser-396); and SMI-31 (1 :
15 000, mouse monoclonal, Sternberger, recognizes phosphorylated neurofilaments).

Results
Gross findings
The brain weight was 1115 g. External gross examination
disclosed atrophy in the frontal and temporal lobes. No
laterality of atrophy was noticed. The most severe atrophy
was found on both sides of the superior temporal gyri, especially in their posterior two-thirds (Fig. 1, asterisk). The
atrophy was markedly diminished in the rest of the temporal lobe. In the frontal lobe, the posterior part of the inferior frontal gyrus, especially the pars opercularis, was
most conspicuously atrophic. The parietal and occipital
lobes showed externally normal convolutions. The lateral
ventricle was dilated markedly with slight flattening of
the caudate nuclei and moderate dilatation was noticed in
the third ventricle. The substantia nigra was pale.

Microscopic findings
The most pronounced degeneration, consisting of neuronal
loss, spongy state and gliosis, was seen in the superior and
transverse temporal gyri, where all layers were affected by
extreme thinning (Fig. 2). The same type of degeneration
was seen in the upper cortical layers of the insular cortex
and the basal part of the inferior frontal gyrus. Degeneration, but of a milder degree, extended extensively in the
posterior frontal lobe, precentral gyrus, postcentral gyrus,

supraparietal lobulus, infraparietal lobulus, and the remainder of the temporal lobe. Diffuse fibrillary gliosis
was observed in the white matter with a distribution corresponding to the cortical degeneration (Fig. 3a). The subcortical grey matter presented neuronal loss and gliosis
that was severe in the substantia nigra (Fig. 3b), and moderate to slight in the ventral part of the thalamus, globus
pallidus, striate body, the lateral part of the amygdaloid
nucleus, and the locus ceruleus. Only slight glial proliferation without apparent neuronal depletion was observed
in the subthalamic nucleus, red nucleus, dentate nucleus,
tectal region of the brain stem, and inferior olivary nucleus.
Accompanying cerebrovascular involvement was not
observed. Cytopathologically, achromatic ballooned neurons that reacted with SMI-31 antibody were scattered in
the affected cerebral cortex (Fig. 4a, b). On Bodian staining, Pick’s bodies and senile plaques could not be found.
Only a few neurofibrillary tangles were found in the entorhinal pre-alpha layer and substantia nigra, where no
Lewy bodies were seen. In contrast to the paucity of argyrophilic abnormalities detected by Bodian silver impregnation, the modified G-B method and anti-tau immunostaining revealed various types of cytoskeletal abnormalities, which coincide with those reported in CBD, in both
neurons and glia. The most conspicuous finding was the
massive argyrophilic and tau-positive fibrillar or granular
structures, which we designate argyrophilic threads in this
report. Argyrophilic threads were most prominent in the
affected cortical and subcortical regions, but they were
also observed in the relatively well preserved cortex (Fig.
5). In the subcortical regions, they were distributed preferentially in the thalamus, striatum, pallidum, substantia
nigra, tectal area of the brain stem, and inferior olivary
nucleus. This distribution pattern of argyrophilic threads
was almost equivalent to that of the degenerating area.
However, the threads covered a broader area, extending
beyond the region of neuronal degeneration. Among the
argyrophilic threads, scattered coiled bodies, previously
reported to be oligodendroglial [8, 26], were found. Astrocytic plaques (Fig. 6), which are known to be of astrocyte origin [5, 16], were also distributed in the upper cortical layer. Diffusely or granularly argyrophilic and tauimmunolabeled neurons (pre-tangles) were also widely
distributed in the degenerating cerebral cortex (Fig. 4 arrows, Fig. 7).

Fig. 1 On the left side, the brain exhibits severe atrophy in the superior temporal gyrus (asterisk) and the posterior part of the inferior frontal gyrus. A small defect in the angular region is an artifact
at autopsy
Fig. 2 In the superior temporal gyrus, all of the layers show
marked degeneration, which consists of neuronal loss, spongy state
and glial proliferation. Hematoxylin and eosin, × 50
Fig. 3 Holzer staining reveals fibrillary gliosis most prominently
in the atrophied superior temporal gyrus (a). The substantia nigra
(b), globus pallidus (a) and a part of the thalamus (a) are also sites
of degeneration with fibrillary gliosis

F

her admission, although she retained her ability to engage in daily
living activities and could manage household affairs somehow, she
could only say “chott-chott” and could not understand spoken language at all, later showing total aphasia. On neurological examination, she had muscle rigidity and nuchal dystonia, and had a smallstepped gait. Later, she became apathetic and indifferent to her environment and presented dementia. She was confined to her bed
due to pneumonia 8 months after her admission. She had severe
neck rigidity, with her neck bent posteriorly and muscle rigidity of
the limbs. Disturbance of eye movement was not shown clearly.
Eventually she became completely mute and apathetic, and she
died at the age of 67 years, 10 years after the onset of symptoms.
The clinical diagnosis was atypical Pick’s disease.

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Discussion
Although, she ultimately developed severe dementia, our
patient showed progressive aphasia without decline of her
ability to manage her household in the first several years
of illness. Neuropathologically, cerebral involvement was
accentuated in the superior temporal gyrus and subsequently in the frontal operculum. The degeneration of
subcortical grey matter was most prominent in the substantia nigra, but a lesser degree of degeneration was also
seen in the thalamus, globus pallidus and striatum. This
regional predilection of degeneration observed in the subcortical grey is analogous to that described in previous reports of CBD [6, 22]. The clinical diagnosis of this case
was atypical Pick’s disease and it was at first discussed
within the context of Pick’s disease [14], though crucial
contradictions were noticed. Specifically, in Pick’s disease, the superior temporal and transverse gyri are usually
better preserved than the other temporal gyri [13] and,
moreover, the substantia nigra, though its degeneration
has been pointed out in some cases [11], is never affected
to the severe degree seen in this case. No Pick’s body was
found in the hippocampal region and the cerebral cortex.
The behavioral and personality changes did not occur in
this patient until late stages of her clinical course. Pathological findings, particularly the appearance of massive
tau-positive structures, differ from the concept of frontotemporal dementia proposed by the Lund and Manchester groups [3]. In recently reported cases of CBD prominent cytoskeletal abnormalities occurring in both neuron
and glia are pointed out [5, 8, 9, 17, 18, 23, 24], which had
previously not been noticed. Several types of G-B-positive and tau-positive structures are reported to predominate in the degenerating regions. Among them, massive
collections of argyrophilic threads, a considerable part of
which are thought to occupy the inner and outer loops of
myelin [9], are the most prominent finding [23]. Oligodendroglial coiled bodies [2, 10, 26] are also found scattered among these argyrophilic threads. In contrast to the
rare occurrence of neurofibrillary tangles, cortical neurons
are often diffusely argyrophilic and tau-immunoreactive
Fig. 4 Hematoxylin and eosin staining reveals achromatic ballooned neurons (a), which exhibit a positive reaction to SMI-31
antibody (b). They are scattered throughout the degenerating cerebral cortex. × 825
Fig. 5 Massive tau-positive structures are distributed in a broader
area extending beyond the severely degenerated regions. “Argyrophilic threads” form bundles or meshwork. Among them, taupositive cellular components including pre-tangles (arrows) are
also scattered. The precentral gyrus is stained by phosphorylated
tau antibody (C5). × 170
Fig. 6 Astrocytic plaques, which originate from protoplasmic astrocytes, are observed mainly in the upper layer of the cerebral cortex. C5 immunostaining, × 330
Fig. 7 Diffusely or granularly tau-immunolabeled neurons (pretangles) are commonly found throughout the cerebral cortex but
the neurofibrillary tangles cannot be seen. C5 immunostaining, ×
825

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Table 1 Survey of the initial cerebral symptom and cortical focus in 28 cases of corticobasal degeneration
Author

Age/
sex

Most affected cortical region

Main initial cerebral symptom

Rebeiz et al. (1968)

68/F
67/M
72/F
63/M
72/F
71/M
65/F
70/F
62/F
68/M
78/M
74/M
58/M
65/F
77/F
72/F
68/M
74/F
52/M
78/F
73/M
73/M
77/F
71/M
69/F
73/M
49/M
67/F

Posterior frontal and parietal regions (r > l)
Superior frontoparietal region (r > l)
Narrowing of frontal convolutions
Frontal lobe
Frontal lobe and superior temporal gyrus
Superior parietal region (l > r)
Precentral and postcentral gyri
Parietal lobe
Mild gyral atrophy of both cerebral hemispheres
Central frontoparietal cortex
Parasylvian region (l > r)
Frontal cortical atrophy
Frontal lobe
Parietal lobe
Precentral gyrus (l > r)
Precentral gyrus
Around central sulcus (r > l)
Frontal lobe
Superior parietal cortex (l > r)
Parietal cortex (l > r)
Frontal and parietal cortices
Frontal and parietal lobes
Superior frontal gyrus, hippocampus
Frontal lobe
Superior frontal gyrus
Superior temporal gyrus and frontal operculum (r > l)
Superior temporal gyrus (l > r)
Superior temporal gyrus

Motor and sensory disturbance (l > r)
Motor and sensory disturbance (l > r)
Walking difficulty
Personality change
Cognitive decline and dysphasia
Clumsiness hand (r > l)
Speech and gait disturbance
Clumsiness and alien hand (l > r)
Bradykinesia
Clumsiness and apraxia of left hand
Bradykinesia and nonfluent aphasia
Cognitive decline
Behavioral change and gait disturbance
Clumsiness of left extremities
Gait and writing difficulty (r > l)
Clumsiness of right extremities
Clumsiness of left hand
Clumsiness and weakness of right hand
Walking difficulty
Sensory disturbance (r > l)
Walking difficulty and behavioral disorder
Language dysfunction
Cortical dementia
Not mentioned
Personality change and behavioral disorder
Hearing loss and aphasia
Sensory aphasia
Hearing loss and sensory aphasia

Clark et al. (1986)
Gibb et al. (1989)
Riley et al. (1990)
Lippa et al. (1990)
Paulus and Selim (1990)
Nukina et al. (1992)
Mori et al. (1994)
Uchihara et al. (1994)
Horoupian and Chu (1994)
Rinne et al. (1994)
Wakabayashi et al. (1994)
Oda et al. (1995)
Arima et al. (1994)
Yoshimura et al. (1995)
Present case

[23, 24]. In the same cortical area concentric clusters of
stubby fibers, which resemble senile plaques, are noted.
They were confirmed to be formed in astrocytes and were
designated astrocytic plaques; they are one of the characteristic findings of CBD [5] but are also observed in an
atypical case of progressive supranuclear palsy [16]. In
the present case, all of these abnormal structures were
present in the same form as in other reports of cases of
CBD describing these structures [5, 23].
Among neuropathologically evaluated cases of CBD
(Table 1), some similar cases representing progressive aphasia and accentuated focus in superior temporal gyrus are noticed. Arima et al. [1] described a case of corticonigral degeneration involving Broca’s, Wernicke’s and supplemental
motor areas, which presented primary progressive aphasia
and hearing loss as initial symptoms. This case showed accompanying achromatic neurons and argyrophilic, tau-positive inclusions in neurons and later massive collections of
argyrophilic threads and coiled bodies were demonstrated
[9]. Yoshimura et al. [27] regard a case to be CBD in which
slowly progressive aphasia and severe neuronal loss and
gliosis with neuronal achromasia in superior temporal gyrus
are described. These two cases exhibited serious degeneration in the substantia nigra and degeneration in a part of the
thalamus, globus pallidus and striatum. Including our case,
these cases form a subgroup of CBD.
The authors’s overview of CBD cases also revealed another type, in which the focus of the cerebral lesion is sit-

uated in the frontal region (Table 1). Recently, Oda et al.
[18] reported a case of CBD with severe atrophy in the
frontal lobe, especially in the superior frontal gyrus, accompanying severe degeneration in the substantia nigra.
Though this case was clinically diagnosed as frontal
Pick’s disease, histological examinations revealed ballooned neurons and massive tau-positive cytoskeletal abnormalities in neurons and glial cells. Rinne et al. [22]
mentioned one distinctive case presenting prominent personality and behavioral changes, which resembled Pick’s
disease. However, this case was pathologically diagnosed
as CBD based on the distribution of swollen ballooned
neurons in the frontal and parietal lobes in addition to basophilic inclusions in the substantia nigra and other subcortical nuclei. Rinne et al. referred to three similar cases
reported by Clark et al. [4], Lippa et al. [12] and Paulus
and Selim [19] and discussed the possibility of clinicopathological overlapping of Pick’s disease and CBD. Our
preliminary survey of 25 cases of clinicopathologically
confirmed Pick’s disease using the G-B method, however,
revealed that none of the Pick’s cases showed accompanying massive G-B-positive abnormality except for Pick’s
bodies and occasional neurofibrillary tangles, coiled bodies or argyrophilic threads (unpublished data).
In summary, CBD has fairly consistent subcortical involvement, which is observed most prominently in the
substantia nigra and to a lesser degree in the thalamus,
pallidum and striatum, while in almost all cases, the sub-

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thalamic nucleus and dentato-rubral system are relatively
well preserved. In contrast, the cerebral lesions are rather
diverse. In addition to the main group of CBD, in which
the main cortical lesion is located around the central fissure, there are some variations of cortical focus, which explains the clinical diversity observed in CBD. This phenomenon bears some resemblance to the features seen in
Pick’s disease, which includes cortical subtypes other
than the common frontotemporal form. The clinical spectrum of primary progressive aphasia is wide-ranging and
is presently regarded to be a symptom-complex [25].
Some cases of primary progressive aphasia may be CBD
with the prominent cortical lesion in the language center.
Acknowledgements We are very grateful to Drs. H. Mori and Y.
Ihara for their generous gift of antibodies. This work was supported by a grant from the Public Health Bureau of Tokyo Metropolitan Government.

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