Supplementary Material for: Detection of abdominal lymph node metastasis from pancreatic neuroendocrine tumor by somatostatin receptor scintigraphy: Comparison with somatostatin receptors type 2 immunostaining

We report a 58-year-old male with a histopathological-proven grade 2 (G2) pancreatic neuroendocrine neoplasm and multiple abdominal node metastases by use of a laparoscopic pancreatic body and tail resection procedure, plus abdominal lymph node dissection. A primary pancreatic tail neuroendocrine tumor sized 20×25 mm was detected by contrast-enhanced CT, somatostatin receptor scintigraphy (SRS), and fluorodeoxyglucose positron emission tomography (FDG-PET) examinations, and pathologically diagnosed as a pancreatic neuroendocrine tumor (PNET, G2) based on positive immunostaining for somatostatin receptor (SSTR) type 2. Of three metastatic histopathological lymph nodes, two measured 18×21 and 10×12 mm, respectively, with whole strong SSTR immunostaining showing moderate uptake in SRS findings, whereas the other node, sized 8×10 mm, had strong SSTR immunostaining only in a small 6×6-mm sized portion and showed no uptake in SRS findings, likely because of the limited spatial resolution of scintigraphy. On the other hand, only the largest node (18×21 mm) was visualized by FDG-PET. SRS may be useful for metastatic lymph node diagnosis based on SSTR immunostaining, though a disadvantage is the spatial resolution limitation.

本研究报道1例58岁男性患者，经组织病理学证实为2级（G2）胰腺神经内分泌肿瘤，且合并多发腹部淋巴结转移；患者接受了腹腔镜胰体尾切除术联合腹部淋巴结清扫术。通过增强CT、生长抑素受体显像（somatostatin receptor scintigraphy, SRS）及氟代脱氧葡萄糖正电子发射断层显像（fluorodeoxyglucose positron emission tomography, FDG-PET）检查，检出1枚直径为20×25 mm的胰腺尾部原发性神经内分泌肿瘤；结合生长抑素受体2型（somatostatin receptor type 2, SSTR2）免疫组化染色阳性结果，病理诊断为胰腺神经内分泌肿瘤（PNET, G2）。送检的3枚转移性淋巴结中，2枚分别为18×21 mm与10×12 mm，其SSTR免疫组化均呈强阳性，对应SRS显像表现为中度摄取；剩余1枚直径为8×10 mm的淋巴结仅在6×6 mm的局部区域呈现SSTR强阳性，SRS显像未显示摄取，这可能与显像的空间分辨率有限有关。另一方面，仅最大的那枚转移性淋巴结（18×21 mm）可通过FDG-PET显像检出。本研究结果提示，基于SSTR免疫组化特征，SRS或可用于转移性淋巴结的诊断，但其存在空间分辨率不足的局限性。