The Department of Pathology, Division of Dermatopathology, The Ohio State University Wexner Medical Center (OSUWMC), Columbus, Ohio, USA.
University of Calgary Diagnostic and Scientific Centre, Calgary, Alberta, Canada.
J Cutan Pathol. 2021 Jul;48(7):847-855. doi: 10.1111/cup.13942. Epub 2021 Jan 7.
Myoepithelial tumors comprise a group of mesenchymal lesions that show heterogeneous histomorphological features, including dual epithelial, neural, and myoid differentiation. Cutaneous myoepithelioma is a rare neoplasm that is composed primarily of myoepithelial cells and represents one end of a histopathological spectrum of cutaneous myoepithelial neoplasms including chondroid syringoma and myoepithelial carcinoma. These tumors display a wide histopathological spectrum and immunophenotypical profile often showing epithelial and myoepithelial differentiation. In this series, we studied 35 cases of cutaneous myoepitheliomas. Our cases highlighted the broad histopathological range where most cases showed a non-infiltrative and non-encapsulated tumor exclusively located in the dermis and with no subcutaneous involvement. The majority of our cases had a solid growth pattern (syncytial pattern) and the remainder of cases had a multinodular growth pattern. The tumor cells were epithelioid in 23 cases, spindled in eight cases and there was a mixture of epithelioid and spindled cells in four cases. Mitotic figures ranged from 0 to 5 per 10 HPF. By immunohistochemistry epithelial membrane antigen (EMA) was expressed in 59% of cases S100 was positive in 88% of cases, CAM 5.2 was positive in 16% of cases, AE1/AE3 was positive in 44% of cases, p63 was positive in 17% of cases, smooth muscle actin was positive in 38% of cases, desmin was positive in 6% of cases, calponin was positive in 22% of cases, and glial fibrillary acidic protein was positive in 36% of cases. In addition, there were five cases without EMA, keratin, or p63 expression that only showed S100 expression. We describe a large series of cutaneous myoepitheliomas delineating their histomorphological spectrum and immunophenotypical profile. Awareness of some of the unusual histopathological features and the heterogeneous immunohistochemical may pose difficulties for the diagnosis.
肌上皮肿瘤包括一组具有异质性组织形态学特征的间叶病变，包括双上皮、神经和肌源性分化。皮肤肌上皮瘤是一种罕见的肿瘤，主要由肌上皮细胞组成，代表皮肤肌上皮肿瘤组织病理学谱的一端，包括软骨瘤性汗腺瘤和肌上皮癌。这些肿瘤显示出广泛的组织病理学谱和免疫表型特征，通常显示上皮和肌上皮分化。在本系列中，我们研究了 35 例皮肤肌上皮瘤。我们的病例突出了广泛的组织病理学范围，大多数病例显示为非浸润性和非包膜性肿瘤，仅位于真皮内，无皮下累及。我们的大多数病例具有实性生长模式（合胞体模式），其余病例具有多结节生长模式。肿瘤细胞在 23 例中为上皮样，在 8 例中为梭形，在 4 例中为上皮样和梭形细胞混合。有丝分裂象范围为每 10 HPF 0-5 个。免疫组织化学染色显示上皮膜抗原（EMA）在 59%的病例中表达，S100 在 88%的病例中阳性，CAM5.2 在 16%的病例中阳性，AE1/AE3 在 44%的病例中阳性，p63 在 17%的病例中阳性，平滑肌肌动蛋白在 38%的病例中阳性，结蛋白在 6%的病例中阳性，钙调蛋白在 22%的病例中阳性，胶质纤维酸性蛋白在 36%的病例中阳性。此外，有 5 例无 EMA、角蛋白或 p63 表达，仅显示 S100 表达。我们描述了一个大型皮肤肌上皮瘤系列，描绘了它们的组织形态学谱和免疫表型特征。一些不常见的组织病理学特征和异质性免疫组织化学可能会对诊断造成困难。
