Pathologic Diagnosis of Renal Cell Carcinoma in the Era of the 2022 World Health Organization Classification: Key Points for Clinicians

Abstract

The remarkable advances in our understanding of renal tumor pathogenesis, driven by the widespread application of molecular testing, are reflected in the latest 2022 World Health Organization classification. This updated classification categorizes renal cell carcinoma (RCC) into morphologically and molecularly defined RCCs. It includes updates to existing entities and introduces newly established and provisional entities. A standard macroscopic and microscopic evaluation is typically sufficient for diagnosing morphologically defined RCCs and serves as the initial step in the identification of molecularly defined entities. In cases where classification based solely on histologic examination is challenging, a limited panel of immunohistochemical stains can be employed to aid in the diagnosis, with molecular testing for validation if necessary. Therefore, this review explores the key clinical, pathological, and molecular features essential for classifying both the commonly encountered morphologically defined RCCs and the less common but clinically significant molecularly defined RCCs. The goal is to increase awareness of these RCC subtypes among clinicians and promote a deeper understanding of the pathological diagnostic process, ultimately improving patient care.

Keywords

• renal cell carcinomas
• world health organization
• classification
• histology
• immunohistochemistry
• diagnostic molecular pathology