Papillary renal cell carcinoma: Papillary renal cell carcinoma accounts for about 7%-14% of renal cell carcinoma, and is the second most common renal cell carcinoma after clear cell renal cell carcinoma. Its age of onset, male to female incidence rate ratio, symptoms and signs are similar to those of renal clear cell carcinoma.
- Grand body examination: lesions involving bilateral kidneys and multifocal are more common than clear cell carcinoma; they are mostly grayish-pink in color, with hemorrhage, necrosis, and cystic changes.
- Histopathology: It is divided into 2 subtypes, type I and type II, based on histopathological changes. The tumor cells consist of papillary or tubular structures with a ciliated vascular axis, with foamy macrophages and cholesterol crystals in the papillary core; the tumor cells are small and have little cytoplasm (type I) or the tumor cells have abundant eosinophilic cytoplasm and high nuclear grade (type II), with areas of necrosis, sarcomatous differentiation, and transverse myeloid differentiation. The prognosis of patients with type I papillary renal cell carcinoma is better than that of patients with type II.
- Commonly used immunohistochemical antibodies: Similar to clear cell renal cell carcinoma, available studies suggest that papillary renal cell carcinoma is positive for CK7, has a higher rate of P504S positivity, and has a higher rate of type I than type II positivity. Immunohistochemical staining is not necessary for diagnosis and is used only in difficult cases.
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