Zhang Dan, Wang Chaoshan, Zhang Haorui, Yang Wenmin, Nie Ling
Department of Pathology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, Jiangsu Province, China.
Department of Pathology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, Jiangsu Province, China.
Ann Diagn Pathol. 2025 Jul 14;79:152531. doi: 10.1016/j.anndiagpath.2025.152531.
Parotid carcinoma showing thymus-like element (CASTLE) is positive for the immunohistochemical markers CD5 and CD117. However, the specificity of the markers has not been evaluated in parotid tumors with a squamous phenotype. This study aims to validate the efficiency of CD5, CD117, and INSM1 in distinguishing CASTLE from other parotid tumors with a squamous phenotype, including squamous cell carcinoma (SCC, n = 4), lymphoepithelial carcinoma (LEC, n = 5), and pleomorphic adenoma with squamous differentiation (PA-SD, n = 3). The parotid CASTLE exhibited diffusely CD5 membranous positivity (Immunoreactive Score, IRS = 12) and moderate INSM1 nuclear expression (IRS = 6), while SCC, PA-SD, and LEC showed negligible CD5 (IRS ≤ 2) and weak/focal INSM1 (IRS ≤ 3) expression. Although CD117 was diffusely positive in CASTLE, it was moderately to strongly expressed in the LECs (IRS = 9), limiting its diagnostic utility in differential diagnosis. EBER in situ hybridization (ISH) confirmed EBV association in all LECs but not in the CASTLE. In summary, simultaneous CD5 and INSM1 expression may serve as a distinct feature for parotid CASTLE, facilitating differential diagnosis in salivary gland pathology. In addition, EBER ISH remains essential to exclude LEC.
具有胸腺样成分的腮腺癌（CASTLE）对免疫组化标志物CD5和CD117呈阳性。然而，这些标志物在具有鳞状表型的腮腺肿瘤中的特异性尚未得到评估。本研究旨在验证CD5、CD117和INSM1在区分CASTLE与其他具有鳞状表型的腮腺肿瘤中的有效性，这些肿瘤包括鳞状细胞癌（SCC，n = 4）、淋巴上皮癌（LEC，n = 5）和具有鳞状分化的多形性腺瘤（PA-SD，n = 3）。腮腺CASTLE表现为CD5弥漫性膜阳性（免疫反应评分，IRS = 12）和INSM1中等程度核表达（IRS = 6），而SCC、PA-SD和LEC的CD5表达可忽略不计（IRS≤2），INSM1表达为弱/局灶性（IRS≤3）。尽管CD117在CASTLE中弥漫性阳性，但在LEC中呈中度至强表达（IRS = 9），限制了其在鉴别诊断中的应用。EBER原位杂交（ISH）证实所有LEC中存在EBV关联，但CASTLE中不存在。总之，CD5和INSM1同时表达可能是腮腺CASTLE的一个独特特征，有助于涎腺病理学中的鉴别诊断。此外，EBER ISH对于排除LEC仍然至关重要。
