La médula renal normal y patológica The normal and abnormal renal medulla

SUMMARY Background: The renal medulla is composed of a complex system of tubules, blood vessels and interstitium, which the general pathologist often are unfamiliar with. Methods: An in depth review of the literature and of material from our archives related to the pathology of the renal medulla was made. Results: Interesting data on normal and abnormal development, microscopic anatomy, histology, immunohistochemistry, physiology, and pathology, including renal medulla differentiation disorders (multicystic renal dysplasia, adult and infantile type polycystic diseases, cystic medullary disease), inflammatory diseases (xanthogranulomatous pyelonephritis, malakoplakia) and neoplasias (oncocytoma, atypical oncocytic tumour, chromophobe renal cell carcinoma, collecting duct carcinoma, urothelial carcinoma, other carcinomas, renomedullary fibroma and metastatic tumours), was reviewed. Conclusions: A comprehensive knowledge of the genesis, function, and pathology of the renal medulla would result in a greater interest being taken in an area often ignored by pathologists.