Ando Takashi, Yokoi Fuji, Riku Yuichi, Akagi Akio, Miyahara Hiroaki, Hasegawa Masato, Katsuno Masahisa, Yoshida Mari, Iwasaki Yasushi
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Japan.
Neuropathology. 2021 Oct;41(5):376-380. doi: 10.1111/neup.12745. Epub 2021 Jul 28.
The hot cross bun (HCB) sign encompasses a cross-shaped hyperintensity area in the pons on axial T2-weighted magnetic resonance imaging (MRI). The HCB sign is characteristic of multiple system atrophy (MSA) and has occasionally been observed in other neurological disorders. Here, we report an autopsied case of corticobasal degeneration (CBD) that showed the HCB sign. A female patient presented with progressive gait disturbance and cognitive impairment at the age of 60 years. A neurological examination revealed dysarthria, muscle rigidity of the limbs, akinesia, truncal ataxia, urinary incontinence, and dementia. The HCB sign was observed on a brain MRI at the age of 65 years, and a clinical diagnosis of possible MSA was made. She died of pneumonia at the age of 67 years. A postmortem observation, provided neuropathological findings characteristic of CBD, including the presence of astrocytic plaques, pretangles, neuropil threads, and ballooned neurons in association with four-repeat-tau aggregation. Interestingly, the pons displayed severe neuronal loss and astrogliosis that were prominent in the pontine and raphe nuclei. Myelin sheath depletion was prominent in the transverse fibers of the pontine base and the myelinated fibers of the pontine tegmentum in contrast to relative sparing of the pontine corticospinal tract and medial lemniscus. The cerebellar dentate nucleus exhibited neuronal loss and grumose degeneration. Western blot analysis of sarkosyl-insoluble fractions from brain tissue lysates using an anti-phosphorylated tau antibody identified immunoreactive signal bands in approximately 37-40, 43, 64, and 68 kDa, consistent with CBD. Genetic analysis did not reveal any known pathogenic mutations in the microtubule-associated protein tau gene (MAPT). Our case was characterized by the HCB sign and concordant neuropathological changes in the pons. CBD should be considered an underlying pathology of the HCB sign, even though the pontocerebellar changes would be unusual in CBD cases.
热十字面包征（HCB征）是指在轴位T2加权磁共振成像（MRI）上脑桥出现的十字形高信号区。HCB征是多系统萎缩（MSA）的特征性表现，偶尔也可见于其他神经系统疾病。在此，我们报告一例经尸检证实的皮质基底节变性（CBD）病例，该病例显示有HCB征。一名60岁女性患者出现进行性步态障碍和认知障碍。神经系统检查发现构音障碍、肢体肌肉僵硬、运动不能、躯干共济失调、尿失禁和痴呆。65岁时脑部MRI检查发现HCB征，临床诊断为可能的MSA。她于67岁时死于肺炎。尸检观察发现具有CBD特征性的神经病理学表现，包括星形胶质细胞斑、前缠结、神经毡丝和气球样神经元，并伴有四重复tau蛋白聚集。有趣的是，脑桥显示出严重的神经元丢失和星形胶质细胞增生，在脑桥核和中缝核中尤为明显。与脑桥皮质脊髓束和内侧丘系相对保留不同，脑桥基底部的横向纤维和脑桥被盖部的有髓纤维髓鞘脱失明显。小脑齿状核出现神经元丢失和颗粒样变性。使用抗磷酸化tau抗体对脑组织裂解物的 Sarkosyl不溶性部分进行蛋白质免疫印迹分析，在约37 - 40、43、64和68 kDa处鉴定出免疫反应性条带，与CBD一致。基因分析未发现微管相关蛋白tau基因（MAPT）的任何已知致病突变。我们的病例以HCB征和脑桥中一致的神经病理学改变为特征。即使脑桥小脑改变在CBD病例中不常见，CBD也应被视为HCB征的潜在病理基础。
