Fetsch P A, Powers C N, Zakowski M F, Abati A
Cytopathology Section, Laboratory of Pathology, National Institutes of Health/National Cancer Institute, Bethesda, Maryland 20892-1500, USA.
Cancer. 1999 Jun 25;87(3):168-72.
Anti-alpha-inhibin, an antibody directed against a peptide hormone, has been shown to be a useful diagnostic aid in surgical pathology material for the identification of sex cord-stromal neoplasms and recently has been described in adrenocortical carcinoma (ACC). The diagnosis of ACC versus renal cell carcinoma (RCC) may be difficult morphologically, particularly in fine-needle aspiration (FNA) material. To date, the immunohistochemical distinction of ACC from RCC is based on a panel of antibodies that include vimentin, cytokeratins, and epithelial membrane antigen. However, the reliability of this panel is weakened by inconsistent staining patterns.
Archival formalin fixed, paraffin embedded cell block sections from 45 FNAs of known primary and metastatic ACC and RCC as well as benign adrenocortical nodules were stained with anti-alpha-inhibin using an avidin-biotin procedure. All samples were microwave pretreated and a biotin block was performed to reduce the background stain due to the high endogenous biotin often present in these types of samples.
All cases of ACC (n = 7; 100%) and benign adrenocortical cells (n = 15; 100%) were immunoreactive with the a-inhibin antibody, showing a diffuse cytoplasmic and granular staining pattern. The staining intensity and number of immunoreactive cells varied within each sample, with the cases of ACC having the greatest proportion of immunoreactive cells and the strongest intensity. None of the cases of RCC (n = 23; 0%) were immunoreactive with anti-alpha-inhibin.
The morphologic distinction of ACC versus RCC in FNA material from renal, adrenal, and metastatic neoplasms is not always feasible based on cytology alone. However, due to the advent of the alpha-inhibin antibody, the reliable distinction of these entities now may be possible. The intense and specific immunostaining pattern for cells of adrenal origin, even in paucicellular samples, suggests potential for the widespread clinical utility of this marker by cytopathologists.
抗α-抑制素是一种针对肽类激素的抗体，已被证明在手术病理材料中有助于诊断性索间质肿瘤，最近在肾上腺皮质癌（ACC）中也有相关报道。ACC与肾细胞癌（RCC）在形态学上的诊断可能存在困难，尤其是在细针穿刺（FNA）材料中。迄今为止，ACC与RCC的免疫组化鉴别基于一组抗体，包括波形蛋白、细胞角蛋白和上皮膜抗原。然而，该抗体组的可靠性因染色模式不一致而受到削弱。
采用抗生物素蛋白-生物素法，对45例已知原发性和转移性ACC、RCC以及良性肾上腺皮质结节的FNA存档福尔马林固定、石蜡包埋细胞块切片进行抗α-抑制素染色。所有样本均经微波预处理，并进行生物素封闭以减少因这类样本中常存在的高内源性生物素导致的背景染色。
所有ACC病例（n = 7；100%）和良性肾上腺皮质细胞（n = 15；100%）对α-抑制素抗体呈免疫反应性，表现为弥漫性胞质和颗粒状染色模式。每个样本中免疫反应性细胞的染色强度和数量各不相同，ACC病例中免疫反应性细胞的比例最高且强度最强。RCC病例（n = 23；0%）均未对抗α-抑制素呈免疫反应性。
仅基于细胞学在肾、肾上腺及转移性肿瘤的FNA材料中区分ACC与RCC在形态学上并不总是可行的。然而，由于α-抑制素抗体的出现，现在有可能可靠地区分这些实体。即使在细胞数量少的样本中，肾上腺来源细胞的强烈且特异性免疫染色模式表明该标志物在临床病理学家中具有广泛应用的潜力。
