Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Radioisotope Research Center, Agency for Health, Safety and Environment, Kyoto University, Kyoto, Japan.
Front Endocrinol (Lausanne). 2023 Aug 31;14:1245573. doi: 10.3389/fendo.2023.1245573. eCollection 2023.
Insulinomas are the most common functioning pancreatic neuroendocrine neoplasms, and these tumors induce hypoglycemia due to hyperinsulinemia. Hypoglycemia caused by insulinomas can cause seizures, coma or death due to the delayed diagnosis. The only curative treatment is surgical resection. To perform curative surgical resection of insulinomas, preoperative localization is crucial. However, localization of insulinomas is often challenging using conventional imaging methods such as computed tomography (CT) and magnetic resonance imaging. Although endoscopic ultrasound (EUS) fine-needle aspiration and selective arterial calcium stimulation test, which can reflect the endocrine character of the tumor, are performed in such cases, these modalities are invasive and require operator-dependent techniques. Additionally, somatostatin receptor (SSTR)-targeted imaging has a relatively low sensitivity for detecting insulinomas due to its low SSTR type 2 expression. Thus, there is an urgent need for developing a noninvasive diagnostic technique which is specific for detecting insulinomas. Consequently, glucagon-like peptide-1 receptor-targeted imaging has recently emerged and gained a wide interest. Recently, we have developed a novel F-labeled exendin-4-based probe conjugated with polyethylene glycol, [F]FB(ePEG12)12-exendin-4 (F-exendin-4), for positron emission tomography (PET) imaging. Here we report a case of insulinoma in which F-exendin-4 PET/CT noninvasively provided critical information for localization.
This is a case of a 58-year-old male with symptomatic hypoglycemia for 10 years; however, a preoperative diagnosis of insulinoma was not established due to the difficulty in differentiating it from an accessory spleen using conventional imaging. Moreover, the patient requested to avoid invasive diagnostic procedures including EUS. F-exendin-4 PET/CT revealed significant uptakes in the pancreatic tail whereas no apparent uptakes were observed in the spleen; thus, curative laparoscopic enucleation of the pancreatic tail was performed. The diagnosis of insulinoma was confirmed histopathological examination. This is the first case report of insulinoma diagnosed using F-exendin-4 PET/CT.
In this case, PET information led to curative resection through enucleation of the pancreas. F-exendin-4 PET/CT may serve as a useful noninvasive clinical tool for insulinoma localization.
胰岛素瘤是最常见的功能性胰腺神经内分泌肿瘤，这些肿瘤由于胰岛素过多而导致低血糖。由于胰岛素瘤引起的低血糖如果诊断不及时，可能导致癫痫发作、昏迷甚至死亡。唯一的根治性治疗方法是手术切除。为了对胰岛素瘤进行根治性手术切除，术前定位至关重要。然而，使用计算机断层扫描（CT）和磁共振成像等常规成像方法对胰岛素瘤进行定位往往具有挑战性。尽管在这种情况下会进行内镜超声（EUS）细针抽吸和选择性动脉钙刺激试验，这些方法可以反映肿瘤的内分泌特征，但这些方法是侵入性的，需要依赖操作者的技术。此外，由于其低表达的生长抑素受体 2 型，生长抑素受体（SSTR）靶向成像对检测胰岛素瘤的敏感性相对较低。因此，迫切需要开发一种针对胰岛素瘤的非侵入性诊断技术。因此，胰高血糖素样肽-1 受体靶向成像最近已经出现并引起了广泛的关注。最近，我们开发了一种新型 F 标记的外啡肽-4 基探针，与聚乙二醇偶联，[F]FB（ePEG12）12-外啡肽-4（F-外啡肽-4），用于正电子发射断层扫描（PET）成像。在这里，我们报告了一例胰岛素瘤病例，F-外啡肽-4 PET/CT 无创性地提供了定位的关键信息。
这是一例 58 岁男性，有 10 年症状性低血糖病史；然而，由于使用常规成像技术难以将其与副脾区分开来，因此术前未确诊为胰岛素瘤。此外，患者要求避免包括 EUS 在内的侵入性诊断程序。F-外啡肽-4 PET/CT 显示胰尾有明显摄取，而脾脏无明显摄取；因此，进行了腹腔镜胰尾切除术。组织病理学检查证实为胰岛素瘤。这是首例使用 F-外啡肽-4 PET/CT 诊断的胰岛素瘤病例报告。
在本例中，通过胰腺的部分切除术，PET 信息为治愈性切除提供了依据。F-外啡肽-4 PET/CT 可能成为胰岛素瘤定位的一种有用的无创临床工具。
