Department of Pathology and Laboratory Medicine, Nova Scotia Health Authority, Central Zone, Halifax, Nova Scotia, Canada.
Department of Pathology, Saint John Regional Hospital, Horizon Health Network, Saint John, New Brunswick, Canada.
Am J Dermatopathol. 2020 Jul;42(7):491-497. doi: 10.1097/DAD.0000000000001605.
Apocrine hidradenomas (AH) once believed to harbor myoepithelial cells are now considered pure epithelial neoplasms. They are categorized separately from adenomyoepitheliomas which consist of apocrine epithelial and myoepithelial components. Reports of myoepithelial tumors arising in AH have suggested a link between the 2. Our goal was to explore whether cases diagnosed on routine microscopy as AH harbored occult myoepithelial elements, which would be disclosed by an immunohistochemical evaluation. Twenty-nine such cases, derived from a teaching collection of one of the authors, formed the basis of the study. Clinical and demographic data were documented, and morphological details of the cases were recorded. A panel of immunohistochemistry (AE1AE3, CK8/18, epithelial membrane antigen, p63, S100 protein, glial fibrillary acid protein, calponin, alpha actin, and others), designed to identify myoepithelial cells, was used. The population consisted of 14 women and 15 men (mean age 55.8; range 26-82 years). The tumors, located on the head/neck (14), limbs (10), and trunk (5), were solid (2) and solid/cystic (27). They exhibited varied (often combined) cytological elements (clear, squamoid, polygonal, and mucinous cells). On immunohistochemistry, aggregates of myoepithelial cells were identified in 5 (17%) cases. Four were calponin+ and AE1AE3+; they occupied ≤30% of tumor volumes and exhibited fusiform cytomorphology. One was S100 protein+ and AE1AE3+; it occupied 70% of tumor volume and exhibited polygonal cytomorphology. The gradation in the volume of myoepithelial elements disclosed by immunohistochemistry in a subset of our cases suggests that AH and adenomyoepitheliomas exist on a biological continuum of adnexal neoplasia. The diagnostic categorization of lesions with dual elements requires further study, but we propose that the term adenomyoepithelioma be restricted to those in which myoepithelial cells constitute ≥25% of tumor volume.
大汗腺汗管瘤（AH）曾经被认为含有肌上皮细胞，现在被认为是纯上皮性肿瘤。它们与腺肌上皮瘤分开分类，后者由大汗腺上皮和肌上皮成分组成。在 AH 中报告的肌上皮肿瘤的发生表明这两种肿瘤之间存在联系。我们的目标是探讨在常规显微镜下诊断为 AH 的病例是否含有隐匿性肌上皮成分，这些成分可以通过免疫组织化学评估来揭示。作者之一的教学收藏中提取了 29 例这样的病例，作为本研究的基础。记录了临床和人口统计学数据，并记录了病例的形态学细节。使用了一组免疫组织化学（AE1AE3、CK8/18、上皮膜抗原、p63、S100 蛋白、胶质纤维酸性蛋白、钙调蛋白、α 肌动蛋白等），旨在识别肌上皮细胞。该人群由 14 名女性和 15 名男性组成（平均年龄 55.8 岁；范围 26-82 岁）。肿瘤位于头/颈部（14 例）、四肢（10 例）和躯干（5 例），为实体性（2 例）和实体性/囊性（27 例）。它们表现出不同的（通常是混合的）细胞学成分（透明细胞、鳞状细胞、多边形细胞和黏液细胞）。免疫组织化学检查显示，5 例（17%）病例中存在肌上皮细胞聚集。其中 4 例为 calponin+和 AE1AE3+；它们占据肿瘤体积的≤30%，具有梭形细胞形态。1 例为 S100 蛋白+和 AE1AE3+；它占据肿瘤体积的 70%，具有多边形细胞形态。免疫组织化学检查揭示了我们部分病例中肌上皮成分体积的梯度变化，表明 AH 和腺肌上皮瘤在附属肿瘤的生物学连续体上存在。具有双重成分的病变的诊断分类需要进一步研究，但我们建议将腺肌上皮瘤这一术语限制用于肌上皮细胞构成肿瘤体积≥25%的病变。
