Abstract：
UNASSIGNED: Squamoid eccrine ductal carcinoma (SEDC) is a poorly documented but likely underrecognized sweat gland malignancy with significant risk for local recurrence and potential for metastasis and rare disease-related mortality. Histopathologically, the tumor demonstrates a biphasic differentiation pattern: superficially, the tumor has squamous differentiation [indistinguishable from well-differentiated cutaneous squamous cell carcinoma (cSCC)], while the deeper aspect has a more infiltrative pattern with prominent ductal differentiation. Diagnosis of SEDC relies upon histopathologic examination alone. Its pathogenesis is poorly understood, and its genomic features have yet to be described. In this article, we characterize the genomic features in a case of SEDC through whole-exome sequencing, then compare its features with cSCC and other eccrine ductal carcinomas. Whole-exome sequencing revealed 30 mutations/Mb with 21 pathogenic or likely pathogenic mutations in total, identified across 14 different genes. The genomic abnormalities identified in this case of SEDC overlap considerably with those found in cSCC but not those of other sweat gland malignancies. The clinical and histopathologic features of SEDC previously reported and the genetic features determined from this case suggest that this tumor may arise initially as a well-differentiated cSCC that subsequently undergoes divergent differentiation focally to resemble a sweat gland malignancy. Genetic analyses of additional cases are warranted to clarify this consideration.
摘要：
■鳞状汗腺导管癌（SEDC）是一种记录较少但可能未得到充分认可的汗腺恶性肿瘤，具有显著的局部复发风险和转移可能性以及罕见的疾病相关死亡率。组织病理学,肿瘤表现出双相分化模式：表面，肿瘤有鳞状分化[与高分化皮肤鳞状细胞癌（cSCC）没有区别]，而更深的方面具有更多的浸润模式，具有明显的导管分化。SEDC的诊断仅依赖于组织病理学检查。其发病机制了解甚少,它的基因组特征还有待描述。在这篇文章中,我们通过全外显子组测序来表征SEDC的基因组特征，然后将其与cSCC和其他内分泌导管癌的特征进行比较。全外显子组测序显示30个突变/Mb，总共有21个致病性或可能的致病性突变，在14个不同的基因中鉴定。在这种情况下，SEDC的基因组异常与cSCC中发现的基因组异常重叠，但与其他汗腺恶性肿瘤的基因组异常重叠。先前报道的SEDC的临床和组织病理学特征以及从该病例确定的遗传特征表明，该肿瘤最初可能是分化良好的cSCC，随后发生分歧分化，类似于汗腺恶性肿瘤。有必要对其他病例进行遗传分析，以澄清这一考虑。
