Hirsch Michelle S, Nascimento Alessandra F
Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
Diagnose Anatomia Patologica e Citopatologia, Rio de Janeiro, RJ, Brazil.
Case Rep Pathol. 2017;2017:6714549. doi: 10.1155/2017/6714549. Epub 2017 May 28.
is important for embryogenesis of the thyroid, Müllerian system, and upper urinary/renal tract, and expression of PAX8 has been described in carcinomas from each of these sites. The sensitivity and specificity of the polyclonal PAX8 antibody in a large cohort of epithelial tumors as well as lymphomas have been previously determined, the latter because polyclonal PAX8 is known to be immunoreactive in nonneoplastic B-cell lymphocytes which are often used as the positive internal control for immunohistochemistry. In this case report, PAX8 was a diagnostic clue for revising a previous diagnosis of unclassified high grade sarcoma to diffuse large B-cell lymphoma. This case report demonstrates a pitfall for PAX8 immunoreactivity and acts as a reminder that lymphoma should be included in the differential diagnosis of a PAX8 positive, epithelial cell marker negative tumor of unknown primary origin.
PAX8对甲状腺、苗勒管系统及上泌尿道/肾脏的胚胎发育很重要，并且在这些部位的癌中均有PAX8表达的相关描述。此前已确定多克隆PAX8抗体在大量上皮性肿瘤及淋巴瘤中的敏感性和特异性，对于淋巴瘤而言，是因为已知多克隆PAX8在非肿瘤性B淋巴细胞中具有免疫反应性，而这些细胞常被用作免疫组织化学的阳性内对照。在本病例报告中，PAX8是将先前未分类的高级别肉瘤诊断修订为弥漫性大B细胞淋巴瘤的诊断线索。本病例报告展示了PAX8免疫反应性的一个陷阱，并提醒我们，对于原发部位不明的PAX8阳性、上皮细胞标志物阴性的肿瘤，在鉴别诊断时应考虑淋巴瘤。
