Castagnoli Helga, Manni Carlo, Marchesani Francesca, Rossi Gloria, Fattori Sara, Capoccetti Francesca
Service Department Macerata Hospital, ASUR Marche AV3, Nuclear Medicine Unit.
Pulmonary Unit ASUR Marche AV3.
Medicine (Baltimore). 2019 Aug;98(35):e16593. doi: 10.1097/MD.0000000000016593.
Limbic encephalitis is one of the most common paraneoplastic neurological disorders (PND). The role of brain Fluorine-18-fluorodeoxyglucose position emission tomography/computed tomography (CT) in paraneoplastic limbic encephalitis (PLE) and of the whole body 18F-FDG PET/CT in this setting, remains still not well defined.
We report a case of a patient with chronic inflammatory rheumatism, psoriasis and Hashimoto thyroiditis and subsequent appearance of static and dynamic ataxia and episodic memory deficit who was diagnosed as PLE combined with small cell lung cancer (SCLC).
The diagnosis of SCLC was made with EBUS-TBNA of a mediastinal lymph node.
Whole-body 18F-FDG PET/CT was performed for the initial staging of SCLC, in the planning of radiotherapy treatment, to evaluate therapeutic response and in the follow-up. A dedicated brain scan was included to the same PET session. Whole-body contrast enhanced computed tomography (CT) and contrast enhanced whole-brain MRI were also performed.
She was administered neoadjuvant chemioterapy with Cisplatin and Etoposide with concomitant radiotherapy treatment. Whole body 18F-FDG PET/CT showed a complete metabolic response already after 3 cycles of chemioterapy. Brain functional study showed a metabolic pattern characterized by the migration of hypermetabolism in the bilateral hippocampal areas during the therapeutic treatment, which correlated with the persistence of clinical symptoms.
In the era of personalized medicine and targeted therapy, this case highlights the importance of the 18F-FDG PET/CT study as an accurate tool to identify PLE and to guide the diagnostic work-up of the underlying tumor. Considering that most of these are 18F-FDG avid tumors and that the 18F-FDG PET/CT scan is often added to the diagnostic work-up when screening patients for malignancy, this functional imaging can play a decisive role.
边缘叶脑炎是最常见的副肿瘤性神经系统疾病（PND）之一。脑氟-18-氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描（CT）在副肿瘤性边缘叶脑炎（PLE）中的作用以及全身18F-FDG PET/CT在这种情况下的作用仍未明确界定。
我们报告一例患有慢性炎症性风湿病、银屑病和桥本甲状腺炎的患者，随后出现静态和动态共济失调以及发作性记忆缺陷，被诊断为PLE合并小细胞肺癌（SCLC）。
通过纵隔淋巴结的超声支气管镜引导针吸活检（EBUS-TBNA）确诊为SCLC。
进行全身18F-FDG PET/CT以进行SCLC的初始分期、放疗治疗规划、评估治疗反应以及随访。在同一次PET检查中还包括专门的脑部扫描。还进行了全身对比增强计算机断层扫描（CT）和对比增强全脑磁共振成像（MRI）。
她接受了顺铂和依托泊苷的新辅助化疗并同时进行放疗。全身18F-FDG PET/CT显示化疗3个周期后即出现完全代谢反应。脑部功能研究显示，治疗期间双侧海马区代谢亢进有迁移现象，这种代谢模式与临床症状的持续存在相关。
在个性化医疗和靶向治疗时代，该病例凸显了18F-FDG PET/CT研究作为识别PLE和指导潜在肿瘤诊断检查的准确工具的重要性。鉴于这些肿瘤大多对18F-FDG摄取增加，并且在筛查恶性肿瘤患者时，18F-FDG PET/CT扫描常被纳入诊断检查，这种功能成像可发挥决定性作用。
