Department of Pathology, Charles University and University Hospital Plzen, Plzen, Czech Republic.
Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary and Alberta Precision Laboratories, Calgary, AB, Canada.
Mod Pathol. 2022 Sep;35(9):1140-1150. doi: 10.1038/s41379-022-01057-z. Epub 2022 Mar 10.
The category of "oncocytic renal tumors'' includes well-recognized entities, such as renal oncocytoma (RO) and eosinophilic variant of chromophobe renal cell carcinoma (eo-ChRCC), as well as a group of "gray zone" oncocytic tumors, with overlapping features between RO and eo-ChRCC that create ongoing diagnostic and classification problems. These types of renal tumors were designated in the past as "hybrid oncocytoma-chromophobe tumors". In a recent update, the Genitourinary Pathology Society (GUPS) proposed the term "oncocytic renal neoplasm of low malignant potential, not further classified", for such solitary and sporadic, somewhat heterogeneous, but relatively indolent tumors, with equivocal RO/eo-ChRCC features. GUPS also proposed that the term "hybrid oncocytic tumor" be reserved for tumors found in a hereditary setting, typically arising as bilateral and multifocal ones (as in Birt-Hogg-Dubé syndrome). More recent developments in the "gray zone" of oncocytic renal tumors revealed that potentially distinct entities may have been "hidden" in this group. Recent studies distinguished two new entities: "Eosinophilic Vacuolated Tumor" (EVT) and "Low-grade Oncocytic Tumor" (LOT). The rapidly accumulated evidence on EVT and LOT has validated the initial findings and has expanded the knowledge on these entities. Both are uniformly benign and are typically found in a sporadic setting, but rarely can be found in patients with tuberous sclerosis complex. Both have readily distinguishable morphologic and immunohistochemical features that separate them from similar renal tumors, without a need for detailed molecular studies. These tumors very frequently harbor TSC/MTOR mutations that are however neither specific nor restricted to these two entities. In this review, we outline a proposal for a working framework on how to classify such low-grade oncocytic renal tumors. We believe that such framework will facilitate their handling in practice and will stimulate further discussions and studies to fully elucidate their spectrum.
“嗜酸细胞性肾肿瘤”这一类别包括公认的实体，如肾嗜酸细胞瘤（RO）和嗜酸性变异型嫌色细胞肾细胞癌（eo-ChRCC），以及一组“灰色地带”嗜酸细胞瘤，其在 RO 和 eo-ChRCC 之间具有重叠特征，导致持续存在诊断和分类问题。这些类型的肾肿瘤过去被指定为“混合嗜酸细胞瘤-嫌色细胞瘤”。在最近的更新中，泌尿生殖系统病理学学会（GUPS）提出了“低度恶性潜能的嗜酸细胞瘤性肾肿瘤，未进一步分类”这一术语，用于此类孤立和散发性、有些混杂但相对惰性的肿瘤，具有不确定的 RO/eo-ChRCC 特征。GUPS 还建议将“混合嗜酸细胞瘤”一词保留用于遗传性肿瘤，通常表现为双侧和多灶性（如 Birt-Hogg-Dubé 综合征）。最近在嗜酸细胞瘤性肾肿瘤的“灰色地带”中出现的新进展表明，可能有不同的实体可能隐藏在这一组中。最近的研究区分了两种新实体：“嗜酸细胞空泡性肿瘤”（EVT）和“低度嗜酸细胞瘤”（LOT）。关于 EVT 和 LOT 的快速积累的证据证实了最初的发现，并扩展了对这些实体的认识。两者均为良性且通常在散发性环境中发现，但在结节性硬化症患者中很少见。两者均具有易于区分的形态学和免疫组织化学特征，使其与类似的肾肿瘤分开，而无需进行详细的分子研究。这些肿瘤经常携带 TSC/MTOR 突变，但这些突变既不特异也不限于这两种实体。在这篇综述中，我们概述了一个如何对这些低度嗜酸细胞瘤性肾肿瘤进行分类的工作框架的建议。我们认为，这样的框架将有助于在实践中处理这些肿瘤，并将激发进一步的讨论和研究，以充分阐明其范围。
