Nephrology, Hospital Universitario Virgen del Rocio, Sevilla, Spain.
Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz UAM and REDINREN, Madrid, Spain.
Diagn Pathol. 2019 May 15;14(1):42. doi: 10.1186/s13000-019-0812-6.
According to WHO, succinate dehydrogenase (SDH)-deficient renal cell carcinoma is characterized by negative immunostaining for SDHB, which remains positive in non-tumor tissue despite germline mutations in the SDHB gene. We now report a patient with a SDHB mutation, c.166_170del (p.Pro56Tyrfs*5) who developed renal cell carcinomas with characteristic morphological features of SDH-deficient renal cell carcinoma but had positive SDHB immunostaining.
Within a 6-year period, the patient developed two different renal cell carcinomas, which had characteristic morphological features of SDH-deficient renal cell carcinoma (uniform cells characteristically displaying eosinophilic granular material intermixed with fewer cells exhibiting clear intracytoplasmic inclusions and bland centered nuclei) but displayed immunohistochemistry for SDHB with a cytoplasmic granular positivity (mitochondrial pattern) in tumor cells. For the second case, this was initially interpreted as positive by IHC, but on review some subtle differences were identified.
SDHB immunostaining may be positive in renal cell carcinoma associated to germline SDHB deficiency which have other typical morphological features. Immunohistochemistry interpretation may be complex.
根据世界卫生组织的定义，琥珀酸脱氢酶（SDH）缺陷型肾细胞癌的特征为 SDHB 免疫组化阴性，尽管 SDHB 基因存在种系突变，但在非肿瘤组织中仍为阳性。我们现报道 1 例 SDHB 基因突变（c.166_170del[p.Pro56Tyrfs*5]）患者，其发生的肾细胞癌具有 SDH 缺陷型肾细胞癌的典型形态特征，但 SDHB 免疫组化染色阳性。
在 6 年期间，该患者先后发生了 2 种不同的肾细胞癌，具有 SDH 缺陷型肾细胞癌的典型形态特征（均匀的细胞通常显示嗜酸性颗粒状物质，与较少的细胞混合，这些细胞表现出清晰的胞质内包涵体和温和的中央核），但肿瘤细胞的 SDHB 免疫组化呈细胞质颗粒阳性（线粒体模式）。对于第 2 例病例，最初的免疫组化结果判读为阳性，但在复查时发现了一些细微差异。
具有其他典型形态特征的与种系 SDHB 缺陷相关的肾细胞癌中，SDHB 免疫组化染色可能为阳性。免疫组化的判读可能较为复杂。
