Stowman Anne M, Mills Stacey E, Wick Mark R
Department of Pathology, Division of Surgical Pathology, University of Virginia Health Sciences Center, Charlottesville, VA.
Am J Surg Pathol. 2016 Sep;40(9):1270-9. doi: 10.1097/PAS.0000000000000678.
Intranodal spindle cell lesions on biopsy are problematic for a surgical pathologist, often requiring an extensive immunohistochemical evaluation with variable and frequently unsatisfactory results. In the absence of a history of malignancy, the differential diagnosis of a spindle cell tumor must include both a primary nodal proliferation and a metastatic process. Particularly challenging are those lesions that share morphologic and immunohistochemical features; spindle cell melanomas (SCM) and interdigitating dendritic cell sarcomas (IDCS) belong to this category. At present, electron microscopy is the only method proposed to distinguish between the 2 entities; however, this method is often unavailable and impractical. In this study, we assessed the comparative immunophenotypes of 18 cases of SCM and 8 cases of IDCS, with particular emphasis on the expression of MUM-1, β-catenin, SOX-10, MiTF, and p75. Our results showed nearly equivalent staining patterns and profiles; 12% and 17% of IDCS and SCM were labeled for MUM-1, 75% and 83% stained for β-catenin, 0% and 24% expressed MiTF, and 100% and 94% labeled for p75, respectively. All cases of IDCS and SCM displayed strong nuclear reactivity for SOX-10. On the basis of our study and pertinent literature, the morphologic and immmunophenotypic features of SCM and IDCS appear to be virtually indistinguishable from one another, raising the question as to whether these 2 entities represent a pathobiologically similar or even identical process.
活检时，淋巴结内的梭形细胞病变给外科病理学家带来了难题，通常需要进行广泛的免疫组织化学评估，结果却各不相同且常常不尽人意。在没有恶性肿瘤病史的情况下，梭形细胞瘤的鉴别诊断必须同时考虑原发性淋巴结增殖和转移过程。特别具有挑战性的是那些具有形态学和免疫组织化学特征的病变；梭形细胞黑色素瘤（SCM）和指状突树突状细胞肉瘤（IDCS）就属于这一类。目前，电子显微镜是唯一被提出用于区分这两种实体的方法；然而，这种方法通常不可用且不切实际。在本研究中，我们评估了18例SCM和8例IDCS的比较免疫表型，特别关注MUM-1、β-连环蛋白、SOX-10、MiTF和p75的表达。我们的结果显示出几乎相同的染色模式和特征；IDCS和SCM分别有12%和17%被MUM-1标记，75%和83%被β-连环蛋白染色，0%和24%表达MiTF，100%和94%被p75标记。所有IDCS和SCM病例对SOX-10均显示出强烈的核反应性。基于我们的研究和相关文献，SCM和IDCS的形态学和免疫表型特征似乎几乎无法区分，这就提出了一个问题，即这两种实体是否代表了病理生物学上相似甚至相同的过程。
