What condition results in a "thyroid-like" appearance of the kidney?

The condition characterized by a "thyroid-like" appearance of the kidney is chronic bacterial pyelonephritis. This distinctive appearance is due to the presence of atrophy and fibrosis of the renal parenchyma, which leads to the accumulation of colloid-like material resembling thyroid tissue, giving the kidneys a "thyroid-like" appearance on histological examination.

Chronic bacterial pyelonephritis typically follows recurrent urinary tract infections, leading to scarring and changes in the kidney architecture. The term "thyroid-like" appearance refers to the eosinophilic staining and the pattern of fibrosis that can be observed, which resembles the microscopy findings of thyroid tissue. In chronic bacterial pyelonephritis, the renal pelvis and calyces may also become dilated as a result of obstructive changes, further contributing to the abnormalities in kidney structure.

This outcome is distinct from the other conditions listed. For instance, acute tubular necrosis primarily causes damage to the renal tubules without the characteristic thyroid-like appearance. Diabetic nephropathy involves changes such as glomerulosclerosis and thickening of the glomerular basement membrane rather than a thyroid-like change. Polycystic kidney disease involves the formation of numerous cysts in the kidneys