Smith K J, Williams J, Corbett D, Skelton H
Departments of Dermatology, University of Alabama-Birmingham, 35294-0009, USA.
Am J Surg Pathol. 2001 Apr;25(4):464-71. doi: 10.1097/00000478-200104000-00005.
Microcystic adnexal carcinoma (MAC) is the prototype for a subset of locally aggressive adnexal carcinomas (LAACs). Ultraviolet radiation (UVR) and UVB signature p53 mutations are implicated in the etiology of the most common cutaneous carcinomas. However in MACs, the role of UVR and p53 mutations is unknown. In addition, controversy still exists regarding the patterns of differentiation within these tumors. The objective of this study was to determine the expression patterns of immunohistochemical markers for p53, Ki-67, c-erbB-2, and Bcl-2 in MACs, and to compare these patterns with two MAC histologic stimulants: sclerosing type basal cell carcinomas (sBCCs) and desmoplastic trichoepitheliomas (dTEs). Other objectives were to compare expression patterns of cytokeratin (CK) AE1/AE3, CK7, CD20, endothelial membrane antigen (EMA), Ber-EP4, CD34, alpha-smooth muscle actin (SMA), and S-100 protein in MACs with its histologic simulators, and to determine the usefulness of all the immunohistochemical studies in diagnosis. Immunohistochemical markers were performed on 10 MACs, 10 sBCCs, and four dTEs. They included p53, Ki-67, c-erbB-2, Bcl-2, CK AE1/AE3, CK7, CD20, EMA, Ber-EP4, CD34, S-100 protein, and alpha-SMA. MACs expressed p53 in less than 25% of the tumor cells in only two cases (20%), and both cases showed only moderately intense staining, whereas 80% of the sBCCs were positive and showed intense staining, and all dTEs were negative. In MACs, less than 5% of the tumor cells were Ki-67 positive, whereas the sBCCs showed 20% to 40% Ki-67-positive tumor cells and dTEs showed rare Ki-67-positive cells. Bcl-2 was expressed focally in MACs, diffusely in sBCCs, and in scattered cells in dTEs. All tumors were negative for c-erbB-2. CD34, CK7, EMA, Ber-EP4, S-100 protein, and alpha-SMA all showed a distinctive pattern of staining in MACs. Although MACs arise commonly in chronically sun-exposed skin, increased expression of p53 is not found frequently. Overexpression of c-erbB-2 does not appear to be a factor in the development and progression of these adnexal tumors. Bcl-2 is expressed in MACs, but not diffusely as in sBCCs. The low level of Ki-67 supports a low proliferative rate, and other immunohistochemical markers support divergent patterns of adnexal differentiation in MACs. Immunohistochemical studies may help to differentiate MAC from sBCCs and dTEs.
微囊性附属器癌（MAC）是局部侵袭性附属器癌（LAAC）子集的原型。紫外线辐射（UVR）和UVB特征性p53突变与最常见皮肤癌的病因有关。然而，在MAC中，UVR和p53突变的作用尚不清楚。此外，关于这些肿瘤内的分化模式仍存在争议。本研究的目的是确定MAC中p53、Ki-67、c-erbB-2和Bcl-2免疫组化标志物的表达模式，并将这些模式与两种MAC组织学模拟物进行比较：硬化型基底细胞癌（sBCC）和促结缔组织增生性毛发上皮瘤（dTE）。其他目的是比较MAC与其组织学模拟物中细胞角蛋白（CK）AE1/AE3、CK7、CD20、内皮膜抗原（EMA）、Ber-EP4、CD34、α平滑肌肌动蛋白（SMA）和S-100蛋白的表达模式，并确定所有免疫组化研究在诊断中的有用性。对10例MAC、10例sBCC和4例dTE进行了免疫组化标志物检测。它们包括p53、Ki-67、c-erbB-2、Bcl-2、CK AE1/AE3、CK7、CD20、EMA、Ber-EP4、CD34、S-100蛋白和α-SMA。仅在2例（20%）MAC中，不到25%的肿瘤细胞表达p53，且这2例均仅显示中度强染色，而80%的sBCC呈阳性并显示强染色，所有dTE均为阴性。在MAC中，不到5%的肿瘤细胞Ki-67呈阳性，而sBCC显示20%至40%的肿瘤细胞Ki-67呈阳性，dTE显示罕见的Ki-67阳性细胞。Bcl-2在MAC中呈局灶性表达，在sBCC中呈弥漫性表达，在dTE中呈散在细胞表达。所有肿瘤c-erbB-2均为阴性。CD3, CK7, EMA, Ber-EP4, S-100蛋白和α-SMA在MAC中均显示出独特的染色模式。尽管MAC常见于长期暴露于阳光下的皮肤，但p53表达增加并不常见。c-erbB-2的过表达似乎不是这些附属器肿瘤发生和进展的一个因素。Bcl-2在MAC中表达，但不像在sBCC中那样弥漫性表达。Ki-67水平低支持增殖率低，其他免疫组化标志物支持MAC中附属器分化的不同模式。免疫组化研究可能有助于将MAC与sBCC和dTE区分开来。
