Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare neoplasm. Diagnosis of SPN requires an integrated approach with aid of radiology, biopsy, cytology, and immunohistochemical stains. Although morphological features in combination with nuclear positivity of β-catenin IHC have been the gold standard of SPN diagnosis, but overlapping morphology and immunohistochemical findings with other entities in differential diagnoses such as pancreatic neuroendocrine tumors and pancreatic ductal adenocarcinoma make the diagnosis of SPN difficult particularly in limited cytology specimens. Lymphoid enhancer-binding factor 1 (LEF1), a key player in the Wnt signaling pathway, has shown promising diagnostic utility in SPN in recent literatures. Methods: In this retrospective study, we evaluated the diagnostic utility of LEF1 IHC in SPN in cytology specimens. LEF1 IHC was performed and compared with β-catenin, synaptophysin, and chromogranin immunostains in 13 SPN and 23 pancreatic neuroendocrine tumors (PanNETs) cytology cases with retrievable cell blocks. Results: LEF1 was positive in 13 of 13 (100%) SPNs and was negative in all PanNETs (0%). Conclusion: LEF1 shows 100% sensitivity and specificity in cytology specimens for SPN and can be valuable immuno­stain in the diagnosis of SPN in cytology cell blocks.
Acta Cytologica

中文翻译：

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LEF1免疫染色在胰腺假性伪乳头状肿瘤细胞学标本中的诊断作用

胰腺的实体假乳头状肿瘤（SPN）是一种罕见的肿瘤。SPN的诊断需要借助放射学，活检，细胞学和免疫组织化学染色的综合方法。尽管结合β-cateninIHC核阳性的形态学特征已成为SPN诊断的金标准，但在形态学和免疫组织化学发现与其他实体（如胰腺神经内分泌肿瘤和胰腺导管腺癌）的鉴别诊断中存在重叠，使得SPN的诊断尤其困难。在有限的细胞学标本中。Wnt信号通路中的关键角色淋巴增强剂结合因子1（LEF1）在最近的文献中已显示出在SPN中有希望的诊断用途。方法：在这项回顾性研究中，我们评估了LEF1 IHC在细胞学标本中SPN中的诊断效用。进行了LEF1 IHC并将其与13例SPN和23例胰腺神经内分泌肿瘤（PanNETs）具有可回收细胞阻滞的细胞学病例中的β-catenin，突触素和嗜铬粒蛋白免疫染色进行比较。结果： LEF1在13个SPN中有13个（100％）为阳性，在所有PanNETs中均为阴性（0％）。结论： LEF1在细胞学标本中对SPN具有100％的敏感性和特异性，对细胞学SPN诊断具有重要的免疫意义。
细胞学学报