Narisawa Yutaka, Inoue Takuya, Nagase Kotaro
Division of Dermatology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan.
Am J Dermatopathol. 2021 Jan 1;43(1):15-20. doi: 10.1097/DAD.0000000000001618.
In skin containing hair follicles, specialized epithelial structures known as "touch domes (TDs)" are located where the Merkel cells are clustered. We explored the histogenetic relationship between intraepidermal and dermal Merkel cell carcinomas (MCCs) and investigated which transformed progenitor cells can develop into intraepidermal MCC. We encountered an association between an extremely rare case of dermal and intraepidermal MCC with squamous cell carcinoma, which was examined using standard immunohistochemical methods with various epithelial, neuroendocrine, and TD markers including several immunohistochemical markers. Differential expression levels of CK20 and CD56 were found between intraepidermal and dermal MCCs, indicating molecularly distinct MCC populations. CK15 and CK17, expressed in TDs, were partially expressed in the intraepidermal neuroendocrine component at the tumor periphery in intraepidermal MCC with squamous cell carcinoma. These differences may suggest that the origin of dermal and intraepidermal MCCs is different under pathological conditions. We hypothesize that intraepidermal MCC is derived from tissue-specific stem cells localized within TDs.
在含有毛囊的皮肤中，一种称为“触觉圆顶（TDs）”的特殊上皮结构位于默克尔细胞聚集的部位。我们探究了表皮内和真皮内默克尔细胞癌（MCC）之间的组织发生关系，并研究了哪些转化的祖细胞可发展为表皮内MCC。我们遇到了一例极其罕见的真皮和表皮内MCC合并鳞状细胞癌的病例，该病例采用了包括多种免疫组化标记物在内的各种上皮、神经内分泌和TD标记物的标准免疫组化方法进行检查。在表皮内和真皮内MCC之间发现了细胞角蛋白20（CK20）和CD56的差异表达水平，表明分子上不同的MCC群体。在TDs中表达的CK15和CK17，在合并鳞状细胞癌的表皮内MCC肿瘤周边的表皮内神经内分泌成分中部分表达。这些差异可能表明在病理条件下，真皮内和表皮内MCC的起源不同。我们推测表皮内MCC源自位于TDs内的组织特异性干细胞。
