Renal replacement lipomatosis: A relatively uncommon and underreported entity

Noncontrast computed tomography (CT) scan of the abdomen showed multiple renal calculi in the left kidney, along with thinned out renal parenchyma. Microscopic examination revealed extensive mature adipose tissue exhibiting degenerative changes, with only scant, separate, microscopically identifiable renal parenchyma exhibiting chronic pyelonephritis, in the form of dense chronic interstitial inflammatory infiltrate, dilated tubules lined by cuboidal to flattened epithelium and filled with casts (thyroidization of tubules), and only an occasional sclerosed glomerulus [Figure 2]c and [Figure 2]d; [Figure 3]. [...]RRL is a relatively uncommon and underdiagnosed entity, which should be kept in mind by the clinicians, radiologists, and pathologists.