HISTORY
Large left cystic renal mass for definition
TECHNIQUE
Helical acquisition postcontrast CT chest/abdomen/pelvis with multiplanar reformats.
DLP: 15 mGycm
FINDINGS
Large, multicystic fluid density mass originating from the left kidney, measuring 118 x 106 x 136mm (AP x TR x CC). Renal claw sign with anteromedial displacement of the renal parenchyma. Thin septations are present throughout the lesion, but there is no appreciable enhancement, calcification or soft tissue component. There appears to be herniation of pedunculated cysts into the renal pelvis (See Stack Key Image). No haemorrhage.
Left renal artery and vein are patent, and pass anteriorly along the medial mass curvature to enter the left renal hilum in the expected anatomic location.
The mass does not encase any adjacent vessels, nor is there any adjacent soft tissue or organ invasion. Surrounding organs, including spleen, liver, pancreas, adrenal glands and bowel are displaced by the mass. Solid organs and abdominal viscera are otherwise normal. Gallbladder is partially decompressed and thin walled. No intra or extrahepatic duct dilatation.
Aorta and IVA are patent, as are their distal branches.
Right kidney measures 6.7cm in bipolar dimension (~86th centile) with normal corticomedullary differentiation and no focal lesion. Right renal vein and artery are patent. No hydronephrosis or hydroureter.
Bladder is normal.
Both adrenal glands are normal.
No small or large bowel obstruction or perforation.
No abdominal or pelvic free fluid.
IMPRESSION
1) Large multicystic lesion arising from the left kidney with no visible enhancing soft tissue components, which correlates with the recent ultrasound. There is local mass effect, but no vascular invasion / thrombus. The imaging appearance is most consistent with a multilocular cystic nephroma (which may be associated with a DICER 1 mutation).