Craniopharyngioma (CP) is mainly classified into two pathological subtypes: adamantinomatous (ACP) and papillary (PCP). CTNNB1 (β-catenin) mutations are detected in ACPs, and the BRAF V600E mutation is detected in PCPs. However, genetic analysis is not always possible in general medical practice. In this study, we investigated whether immunohistochemistry could replace genetic analysis as an aid in subtype diagnosis. Here, 38 CP patients who had undergone their first tumor resection were included. Among the 38 cases, 22 were morphologically diagnosed as ACP, 10 cases were diagnosed as PCP, and six cases were diagnosed as undetermined CP that were morphologically difficult to classify as either ACP or PCP. Results of immunohistochemistry and genetic analysis and clinical features were compared. Based on the immunohistochemistry, 26 (22 ACPs and four undetermined CPs) showed nuclear β-catenin expression, 11 (nine PCPs and two undetermined CPs) exhibited positive BRAF V600E immunostaining, and one PCP showed membranous β-catenin expression and negative BRAF V600E immunostaining. Among the 26 nuclear β-catenin expression cases, 11 had CTNNB1 mutations; however, 15 cases had mutations of neither CTNNB1 nor BRAF V600E. All 11 BRAF V600E immunopositive cases had BRAF V600E mutations. When comparing clinical features, pediatric patients and those with tumor calcification and less solid components on MRI more commonly had nuclear β-catenin expression tumors than BRAF V600E immunopositive tumors, reflecting the differences in clinical features between ACP and PCP. Accordingly, immunohistochemistry can replace genetic analysis as an aid to determine the subtype diagnosis of CP in general medical practice.

颅咽管瘤（CP）主要分为两种病理亚型：金刚瘤（ACP）和乳头状（PCP）。在 ACP 和BRAF中检测到CTNNB1（β-连环蛋白）突变在 PCP 中检测到 V600E 突变。然而，在一般医疗实践中，基因分析并不总是可行的。在这项研究中，我们调查了免疫组织化学是否可以代替遗传分析作为亚型诊断的辅助手段。在这里，包括 38 名接受过第一次肿瘤切除术的 CP 患者。38例中，22例形态学诊断为ACP，10例诊断为PCP，6例诊断为形态学上难以分类为ACP或PCP的未定CP。比较免疫组织化学和遗传分析的结果和临床特征。基于免疫组织化学，26 个（22 个 ACP 和 4 个未确定的 CP）显示核 β-连环蛋白表达，11 个（9 个 PCP 和两个未确定的 CP）显示阳性 BRAF V600E 免疫染色，一名 PCP 显示膜性 β-连环蛋白表达和阴性 BRAF V600E 免疫染色。在 26 例核 β-catenin 表达病例中，11 例有CTNNB1突变；然而，15 例既没有CTNNB1也没有BRAF V600E突变。所有 11 例 BRAF V600E 免疫阳性病例都有BRAF V600E 突变。在比较临床特征时，儿科患者和 MRI 上有肿瘤钙化和较少实性成分的患者比 BRAF V600E 免疫阳性肿瘤更常见核 β-catenin 表达肿瘤，反映了 ACP 和 PCP 之间临床特征的差异。因此，免疫组织化学可以代替遗传分析作为辅助，在一般医疗实践中确定 CP 的亚型诊断。