49 yrs. old male patient with left loin pain

Abstract

Renal sinus cyst are benign. Cysts involving the renal pelvis are classified as Para pelvic or peri pelvic cyst (renal sinus cyst) according to their site of origin. Para pelvic cyst: originate from the adjacent parenchyma and protrude into the renal sinus. Histologically, they are lined with a single epithelial layer. Peri pelvic cyst: originate within the sinus itself and have a lymphatic origin. Non-contrast CT: recommended after USG as Ultrasound demonstrates left hydro nephrosis and failed demonstrating stone.Non-contrast CT: Again, appears as left mild hydro nephrosis without stone and hydro ureter. CT urogram performed and reveals non-dilated left pelvicalyceal system. No stone in kidneys, ureters and urinary bladder. Re-demonstration of cystic structures from left renal pelvis extending alongside of non-dilated pelvicalyceal system. Incidental note:Mesenteric root fat stranding with multiple lymph nodes, representing mesenteric panniculitis. Para pelvic cystThese are simple renal cyst that plunge into the renal sinus from the adjacent renal parenchyma. They are usually single or few and resemble simple renal cortical cyst in morphology. A Para pelvic cyst at times may cause compression of the pelvicalyceal system resulting into hydro nephrosis. Peri pelvic cystThese are frequently bilateral. They appear as water attenuation cysts closely abutting the pelvis and infundibula; rarely cause functional renal derangement by compression. When followed up they remain unchanged in size. They may be confused with hydro nephrosis on NECT and USG (as in this case), but differentiation is very obvious on CECT t as it demonstrates contrast in non-dilated pelvicalyceal system and cyst are seen adjacent to pelvicalyceal system.