Foschini M P, Eusebi V
Department of Oncology, University of Bologna, Bellaria Hospital, Italy.
Semin Diagn Pathol. 2000 May;17(2):162-8.
In the skin, endocrine tumors showing areas with nonendocrine features and nonendocrine tumors showing endocrine differentiation are present. (1) Neuroendocrine carcinomas with nonendocrine differentiation: Merkel cell carcinoma (MCC) of the skin has been frequently described in association with squamous cells carcinoma (SCC) which can arise separately (as synchronous or metachronous lesions) from MCC as well as closely intermixed. In the first event the possibility that the lesions are sustained by same causative factors (among which sun exposure is the most probable) is suggested. In cases of lesions closely intermixed the possibility of an origin from a common precursor is suggested. Furthermore, cases of MCC have been described to contain glandular, melanocytic, striated muscle, and lymphoepithelioma-like features. These latter findings further support the hypothesis of tumors showing divergent differentiations. (2) Nonendocrine tumors showing endocrine differentiation: Basal cell carcinoma (BCC) was the first cutaneous nonendocrine tumor described to contain neuroendocrine granules. Presence of endocrine features were subsequently confirmed with immunohistochemical studies. Endocrine features were then described in sweat gland apocrine and eccrine carcinomas. Endocrine elements present in BCC and in sweat gland carcinomas do not show morphological and immunohistochemical features of Merkel cells. Thus the possibility that these tumors develop an immature Merkel cell or a new type of endocrine cell of the skin is suggested. Tumors with follicular differentiation such as trichoblastomas and trichofolliculomas contain a high number of Merkel cells. As Merkel cells are numerous in hair follicles of human fetal skin, the possibility that these tumors recapitulate the human skin embryogenesis is suggested.
在皮肤中，存在显示非内分泌特征区域的内分泌肿瘤以及显示内分泌分化的非内分泌肿瘤。（1）具有非内分泌分化的神经内分泌癌：皮肤默克尔细胞癌（MCC）常与鳞状细胞癌（SCC）相关联，SCC可与MCC分别出现（作为同步或异时性病变），也可紧密混合。第一种情况提示病变可能由相同的致病因素（其中最可能的是阳光照射）引起。在病变紧密混合的情况下，提示可能起源于共同的前体。此外，已描述MCC病例包含腺性、黑素细胞性、横纹肌性和淋巴上皮瘤样特征。这些发现进一步支持了肿瘤显示不同分化的假说。（2）显示内分泌分化的非内分泌肿瘤：基底细胞癌（BCC）是首个被描述含有神经内分泌颗粒的皮肤非内分泌肿瘤。随后通过免疫组织化学研究证实了内分泌特征的存在。随后在汗腺大汗腺癌和小汗腺癌中也描述了内分泌特征。BCC和汗腺癌中存在的内分泌成分不显示默克尔细胞的形态和免疫组织化学特征。因此提示这些肿瘤可能发展出未成熟的默克尔细胞或一种新型的皮肤内分泌细胞。具有毛囊分化的肿瘤，如毛母细胞瘤和毛囊瘤，含有大量的默克尔细胞。由于默克尔细胞在人类胎儿皮肤的毛囊中数量众多，提示这些肿瘤可能重现了人类皮肤胚胎发生过程。
