Describtion
Kidney tumor
Adult renal cell carcinoma
Clear cell renal cell carcinoma
Definition / general
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Morphologically heterogeneous group of renal carcinomas with clear or eosinophilic cytoplasm, characteristic vasculature and common molecular signature of VHL inactivation
Essential features
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Architecturally and cytologically diverse: solid, alveolar, acinar, cystic growth patterns of cells with clear or eosinophilic cytoplasm
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Characteristic network of small, thin walled, "chicken wire" vasculature
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Inactivation of VHL and upregulation of hypoxia inducible factor
Clinical features
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60% - 80% are found incidentally on imaging
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Metastases often hematogenous via renal veins: lung, liver, bone, soft tissue, adrenal
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Risk factors: adult polycystic disease, smoking, obesity in women, hypertension, von Hippel-Lindau (VHL) disease, tuberous sclerosis (but not via VHL mutations,
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Both papillary and chromophobe have a better prognosis than clear cell RCC
von Hippel-Lindau disease:
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Autosomal dominant syndrome with hemangioblastomas of retina and cerebellum, cysts of pancreas, liver and kidney, clear cell tumors of other sites, papillary cystadenoma of epididymis, pheochromocytoma
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Associated with bilateral or multiple renal cell carcinomas in 50%
Gross:
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Golden yellow tumor (due to lipid content) with hemorrhages and necrosis (image A).
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+/- cystic changes; more solid fleshy (non golden-yellow) area may represent sarcomatoid change (imageB)
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![clear_cell-figureA_Big.jpg clear_cell-figureA_Big.jpg](/getattachment/0885d226-e8d0-4702-be6b-8ab80ea8a9e5/clear_cell-figureA_Big.jpg)
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Microscopic (histologic) description
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Compact, alveolar, tubulocystic or rarely papillary architecture of cells with clear cytoplasm (from lipid / glycogen), distinct but delicate cell boundaries; cell size is 2x normal epithelial tubule cell
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Characteristic network of small, thin walled, "chicken wire" vasculature
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May have angioleiomyomatous features smooth muscle stroma
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myospherulosis overlapping morphologic features of papillary carcinoma
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Some tumors may have pseudopapillary architecture due to high grade changes and loss of cell cohesion
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Grade 1: round or uniform nuclei; nucleoli not discernible or absent
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Grade 2: slightly irregular nuclear contours; nucleoli visible at 400x
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Grade 3: moderately to markedly irregular nuclear contours; nucleoli visible at 100
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Grade 4: multilobular nuclei or bizarre nuclei and large and prominent nucleoli
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![fuhrman_grade-figureA_Big-(1).jpg fuhrman_grade-figureA_Big-(1).jpg](/getattachment/3e175f30-a89c-41a7-9173-0c023d3e1555/fuhrman_grade-figureA_Big-(1).jpg)
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