In 2014,<unk>  was first acknowledged as a renal tumor subtype by the World Health Organization (WHO) considering its distinct genetic, molecular and histologic characteristics. It is further divided into type 1 and type 2 based on morphological features. Type 1<unk>  Type 1<unk> , also known as a renal tumor caused by a genetic predisposition of hereditary papillary renal cancer syndrome, compromises approximately 25% of all<unk> s. In the perspective of immunochemistry, it has a profile of strong CK7 and alpha-methyl acyl-CoA racemase (AMACR) expression at most focal CA-IX expression. Histologically, its epithelium is composed of relatively small-sized simple cuboidal<unk> s lined in a single layer. These<unk> s are well-characterized by basophilic cytoplasm. Due to its solid growth, an extremely compact papillary architecture is often observed. Other morphological characteristics include intracellular hemosiderin and foamy macrophages placed inside of papillary fibrovascular cores or psammoma bodies. In general, the nuclei of type 1<unk>  belong to grade 1-2 of the Fuhrman system. File:Histopathology of<unk>  type 1, high magnification.A micrograph of type 1<unk> , illustrating features of small basophilic<unk> s with scarce cytoplasm. A single layer of<unk> s are surrounding the basal membrane. Foamy macrophages are inside of papillary fibrovascular cores. File:Histopathology of<unk>  type 1, grade 2, with variable density.Type 1<unk> , this case being more compact at right. Type 2<unk>  A micrograph of Type 2<unk> , showing<unk> s containing abundant eosinophilic granular cytoplasm with prominent nucleoli. Accounting for 25% of<unk> s, type 2<unk>  is the pathological subtype that is most commonly associated with hereditary leiomyomatosis and renal<unk>  carcinoma (HLRCC) syndrome. When compared to type 1, it shows more variation in protein expression mostly by loss of CK7. In a gross examination, it shows papillae covered by large<unk> s abundant in eosinophilic cytoplasm. Its large spherical nuclei on papillary cores are arranged in a pseudo-stratified manner. Unlike type 1<unk> , foamy macrophages and psammoma bodies are less common in case of type 2. The majority of type 2<unk>  has high Fuhrman grade nuclei with prominent nucleoli.
Papillary renal cell carcinoma
Renal medullary carcinoma
Renal anaplastic sarcoma
Renal medullary fibroma
Renal oncocytoma
Clear cell renal cell carcinoma
Clear cell papillary renal cell carcinoma
Renal cell carcinoma