Eosinophilic solid and cystic renal cell carcinoma: a review of literature focused on radiological findings and differential diagnosis.

Eosinophilic solid and cystic renal cell carcinoma (ESC-RCC) is a rare type of renal cell carcinoma with inert biological behavior that has not yet been included in the 2016 World Health Organization (WHO) classification, and its imaging manifestations are unclear due to its rarity. Although there have only been a few cases, the CT and MRI findings of ESC-RCC are characterized by its cystic solid structure, according to the proportion of cystic and solid components observed on images, ESC-RCC can be categorized into three types. Especially the Type I, when the cystic-solid components are almost equal, the imaging findings are illustrated as "lotus root-like," which may be helpful in the differential diagnosis of ESC-RCC from other types of renal tumors. In fact, ESC-RCC has diverse radiological appearances, and the differentiation of clear cell renal cell carcinoma, renal oncocytoma, chromophobe renal cell carcinoma, and renal angiomyolipoma remains challenging. This review aims to discuss ESC-RCC with a focus on the radiological findings and differential diagnosis of ESC-RCC.