label: Renal papillary necrosis
label_lc: renal papillary necrosis
description: Premature death of cells in the renal papilla (the apex of a renal pyramid which projects into the cavity of a calyx of the kidney and through which collecting ducts discharge urine). Histologically, one observes pale tissue with typical appearance of coagulative necrosis, affecting the renal papillae. Necrosis can be identified by pyknotic nuclei and simplified, flattened epithelium of proximal tubules. The tubular and glomerular basement membranes are still visible without viable nuclei.