The most common histological variant or renal cell carcinoma is -
Histologically, the features of various types of RCC are as under: 1. Clear cell type RCC (70%): This is the most common pattern. The clear cytoplasm of tumour cells is due to the removal of glycogen and lipid from the cytoplasm during the processing of tissues. The tumour cells have a variety of patterns: solid, trabecular and tubular, separated by delicate vasculature. Majority of clear cell tumours are well differentiated. 2. Papillary type RCC (15%): The tumour cells are arranged in a papillary pattern over the fibrovascular stalks. Psammoma bodies may be seen. The genetic abnormality in these cases lies in MET gene located on chromosome 7 3. Granular cell type RCC (8%): The tumour cells have abundant acidophilic cytoplasm. These tumours have more marked nuclear pleomorphism, hyperchromatism, and cellular atypia. 4. Chromophobe type RCC (5%): This type shows an admixture of pale clear cells with perinuclear halo and acidophilic granular cells. The cytoplasm of these tumour cells contains many vesicles. These cases have genetic defects in the form of multiple losses of whole chromosomes i.e. they have extreme degree of hypodiploidy 5. Sarcomatoid type RCC (1.5%): This is the most anaplastic and poorly differentiated form. The tumour is characterized by whorls of atypical spindle tumour cells. 6. Collecting duct type RCC (0.5%): This is a rare type that occurs in the medulla. It is composed of a single layer of cuboidal tumour cells arranged in a tubular and papillary pattern. Ref: HARSH MOHAN TEXTBOOK OF PATHOLOGY 6th ed. pg no: 695
Clear cell type
Chromophobe type
Papillary type
Tubular type
Urinary tract