Focal Pyelonephritis

40 year old male patient came to emergency with history of right lumbar pain and fever, USG Doppler of right kidney shows focal hypoechoic area in upper pole with small anechoic area within. CT scan of the same patient showwed focal hypoenhancing lesion in upper pole of right kidney with small non enhancing area within. These features are suggestive of focal pyelonephritis with evolution of abscess.

Acute focal pyelonephritis (AFP) is a variant of pyelonephritis in which single or multiple discrete areas show changes of inflammation. The sonographic appearances of AFP are varied and can be echogenic, echopoor or of mixed echogenicity, but are typically described as being echopoor. CT typically shows focal hypoenhancing areas. Imaging is done mainly to identify the complications like intra renal and peri renal abscess.

Wilms' tumour with IVC and right atrial thrombus

CT scan of 15 year old female shows large mass lesion (arrow head) in the left kidney pushing the aorta and IVC to right side and tumour is extending in to left renal vein (short arrow), IVC and into the right atrium (long arrow).

Vascular extension to the vena cava occurs in 4% of Wilms tumor cases and can reach the right atrium in up to 1%. When this happens the thrombus is usually not adherent to the vessel wall, and there is blood flow around it. Preoperative chemotherapy can cause thrombus regression and even resolution. If the thrombus persists after chemotherapy, surgery will be a challenge. On the other hand, if the thrombus invades the vessel wall, its removal may not be feasible. In this situation cavectomy is a good surgical strategy because it provides complete resection. The prerequisite for cavectomy is the absence of blood flow in the vena cava on preoperative Doppler ultrasonography.