腮腺原发性鳞状细胞癌(pSCCP)长期以来一直被认为是一个单独的实体,并包括在唾液腺肿瘤的WHO分类中。然而,头颈部病理学家普遍认为pSCCP异常罕见.然而,有许多出版物描述了pSCCP系列,来自SEER和其他癌症登记数据库的数据错误地表明pSCCP的发病率正在增加.重要的是,pSCCP和转移性(继发性)腮腺鳞状细胞癌(mSCCP)具有几乎相同的组织学特征,pSCCP的诊断只能在排除mSCCP后进行。此外,所有建议支持pSCCP的组织学诊断标准(例如,例如,导管上皮发育不良)可以在明确的mSCCP中遇到,从而代表沿着先前存在的管道的二次生长。鳞状细胞分化在罕见的遗传定义的原发性腮腺癌中也有报道。作为明确的组织学鳞状特征(例如,NUT癌,粘液表皮样癌),通过免疫组织化学(例如,在NUT癌中,类金刚烷胺瘤尤因肉瘤,基底型唾液导管癌,粘液表皮样癌),或两者的组合。在这种情况下的另一个主要问题是,国际疾病分类(ICD)编码系统不区分原发性或转移性疾病,导致大量mSCCP患者被错误分类为pSCCP。免疫组织化学和新的分子生物标志物显著提高了许多涎腺肿瘤的诊断准确性,但直到最近还没有能够准确区分mSCCP和pSCCP的生物标志物.然而,最近的基因组谱分析研究明确表明,迄今为止分析的几乎所有SCCP都具有紫外线(UV)诱导的皮肤来源的mSCCP的典型突变特征.因此,突变特征分析在确定这些肿瘤的皮肤起源方面是非常有用的工具.其他分子研究可能会为这个古老的诊断和临床问题提供新的思路。这篇综述提出了头颈部专家对这一主题的批判性看法。
Primary squamous cell carcinoma of the parotid gland (pSCCP) has long been recognized as a separate entity and is included in the WHO classifications of salivary gland tumors. However, it is widely accepted among head and neck pathologists that pSCCP is exceptionally rare. Yet, there are many publications describing series of pSCCP and data from SEER and other cancer register databases indicate erroneously an increasing incidence of pSCCP. Importantly, pSCCP and metastatic (secondary) squamous cell carcinoma to the parotid gland (mSCCP) have nearly identical histological features, and the diagnosis of pSCCP should only be made after the exclusion of mSCCP. Moreover, all of the histological diagnostic criteria proposed to be in favor of pSCCP (such as, for example, dysplasia of ductal epithelium) can be encountered in unequivocal mSCCP, thereby representing secondary growth along preexistent ducts. Squamous cell differentiation has also been reported in rare genetically defined primary parotid carcinomas, either as unequivocal histological squamous features (e.g., NUT carcinoma, mucoepidermoid carcinoma), by immunohistochemistry (e.g., in NUT carcinoma, adamantinoma-like Ewing sarcoma, basal-type salivary duct carcinoma, mucoepidermoid carcinoma), or a combination of both. Another major issue in this context is that the International Classification of Diseases (ICD) coding system does not distinguish between primary or metastatic disease, resulting in a large number of patients with mSCCP being misclassified as pSCCP. Immunohistochemistry and new molecular biomarkers have significantly improved the accuracy of the diagnosis of many salivary gland neoplasms, but until recently there were no biomarkers that can accurately distinguish between mSCCP and pSCCP. However, recent genomic profiling studies have unequivocally demonstrated that almost all SCCP analyzed to date have an ultraviolet light (UV)-induced mutational signature typical of mSCCP of skin origin. Thus, mutational signature analysis can be a very useful tool in determining the cutaneous origin of these tumors. Additional molecular studies may shed new light on this old diagnostic and clinical problem. This review presents a critical view of head and neck experts on this topic.