Tamm-Horsfall protein deposition

also known as stasis nephropathy

perinatal renal insult of less severe degree than acute cortical necrosis
prolonged nephograms on IV urograms
renal ultrasound:
- increased echogenicity in central portions of pyramids
- preservation of hypoechoic peripheral medulla
- due to deposition of Tamm-Horsfall protein in the tubules
Benign course, usually resolves completely