Sarcomatoid differentiation in chromophobe renal cell carcinoma (ChRCC) is a rare finding and a significant predictor of worse outcomes. When the sarcomatoid component overgrows the conventional component or is the only component on a biopsy, the differential diagnoses encompass a variety of entities. Therefore, we reviewed 22 sarcomatoid ChRCCs and characterized the immunophenotype. Given that renal carcinomas with sarcomatoid features may benefit from immune checkpoint inhibitor-based therapy we also assessed the programmed death-ligand 1 (PD-L1) (28-8) expression. DOG1, CD117, cytokeratin 7, and PAX8 were negative in 100%, 88%, 63%, and 44% of the sarcomatoid components, respectively. GATA3 was expressed in 31% of the conventional components and in 50% of the sarcomatoid components. One conventional and 3 sarcomatoid components expressed PD-L1. Sarcomatoid ChRCCs have a high propensity for metastases and cancer progression. Distant metastatic disease was seen in 73% of the cases and median survival in this cohort was <1 year. The sarcomatoid portion had increased expression of PD-L1 and frequent loss of expression of multiple immunohistochemical markers associated with ChRCC. Half of the sarcomatoid ChRCC exhibited GATA3 expression, 3 of which did not express PAX8.

嫌色细胞肾细胞癌 (ChRCC) 中的肉瘤样分化是一种罕见的发现，也是预后较差的重要预测指标。当肉瘤样成分超过常规成分或者是活检中的唯一成分时，鉴别诊断包括多种实体。因此，我们回顾了 22 种肉瘤样 ChRCC，并对免疫表型进行了表征。鉴于具有肉瘤样特征的肾癌可能受益于基于免疫检查点抑制剂的治疗，我们还评估了程序性死亡配体 1 (PD-L1) (28-8) 的表达。DOG1、CD117、细胞角蛋白 7 和 PAX8 分别在 100%、88%、63% 和 44% 的肉瘤样成分中呈阴性。GATA3 在 31% 的常规成分和 50% 的肉瘤成分中表达。1 个常规成分和 3 个肉瘤样成分表达 PD-L1。肉瘤样 ChRCC 具有很高的转移和癌症进展倾向。73% 的病例出现远处转移性疾病，该队列的中位生存期<1 年。肉瘤样部分的 PD-L1 表达增加，而与 ChRCC 相关的多种免疫组织化学标志物的表达频繁缺失。一半的肉瘤样 ChRCC 表现出 GATA3 表达，其中 3 个不表达 PAX8。