THE PERIRENAL SPACE - RELATIONSHIP OF PATHOLOGICAL PROCESSES TO NORMAL RETROPERITONEAL ANATOMY

The perirenal space may be involved by disease processes that arise wi thin or outside the perirenal space. Key anatomic details that dictate the features of perirenal processes include the renal capsule, the pe rirenal septa, the renal fascia, and the conic shape and inferomedial orientation of the perirenal space, Superiorly, the perirenal space is open to the bare area of the liver. The perirenal spaces communicate with one another at the level of the lower lumbar vertebrae, The hallm ark of perirenal infection is localized or diffuse gas. Chronic urinom a appears as an encapsulated cystic mass, often aligned parallel with the perirenal space, Fat within an apparent spontaneous hematoma of th e perirenal space suggests angiomyolipoma, Renal cell carcinoma, lymph oma, and melanoma are the most common causes of discrete solid masses in the perirenal space; metastases occur due to the characteristic lym phatic and vascular supply of the space. Amyloidosis and fibrosis crea te a nonspecific rind of soft tissue around the kidneys, Diaphragmatic pseudotumor produces a linear ''lesion'' in the perirenal space.