Institute of Pathology, Viollier AG, Allschwil, Switzerland.
Department of Biology, North Park University, 3225 W. Foster Avenue, Chicago Illinois, 60625, USA.
Head Neck Pathol. 2023 Dec;17(4):1052-1057. doi: 10.1007/s12105-023-01592-4. Epub 2023 Oct 17.
Lymphoepithelial carcinoma of the salivary glands (LECSG) is a rare disease in the Western hemisphere that is typically associated with an EBV infection. The molecular mechanisms of LECSG tumorigenesis are poorly understood.
Here we report a case of EBV-associated LECSG with an unusual immunophenotype. The tumor exhibited bi-morphic histological features with a mutually exclusive expression of HER2 and p16. The p16-positive domain of the tumor immunohistochemically co-expressed late membrane protein 1 (LMP-1), while the HER2 positive domain did not. Both tumor regions expressed SSTR2.
In situ hybridization confirmed the EBV origin of the tumor while extensive immunohistochemical characterization and the recently established RNA-based next generation sequencing panel ("SalvGlandDx" panel) did not reveal evidence for another salivary gland neoplasm. No HPV co-infection was detected by in situ hybridization or PCR-based screenings and no ERBB2 gene amplification was detected by fluorescence in situ hybridization.
These findings suggest tumor heterogeneity and lack of genomic aberrations in EBV-associated LECSGs. The heterogenous and unusual immunohistochemical features explain the diagnostic difficulties and simultaneously extend the immunophenotype spectrum of this tumor entity.
涎腺淋巴上皮癌（LECSG）在西半球是一种罕见疾病，通常与 EBV 感染有关。LECSG 肿瘤发生的分子机制尚不清楚。
本文报道了一例伴有不常见免疫表型的 EBV 相关 LECSG。肿瘤表现为双相组织学特征，HER2 和 p16 表达相互排斥。肿瘤的 p16 阳性区域免疫组化共表达晚期膜蛋白 1（LMP-1），而 HER2 阳性区域则不表达。两个肿瘤区域均表达 SSTR2。
原位杂交证实了肿瘤的 EBV 起源，而广泛的免疫组织化学特征和最近建立的基于 RNA 的下一代测序面板（“SalvGlandDx”面板）未发现另一种涎腺肿瘤的证据。原位杂交或基于 PCR 的筛查未检测到 HPV 共感染，荧光原位杂交未检测到 ERBB2 基因扩增。
这些发现表明 EBV 相关 LECSG 存在肿瘤异质性和缺乏基因组异常。异质性和不寻常的免疫组织化学特征解释了诊断困难，并同时扩展了这种肿瘤实体的免疫表型谱。
