ARRS Case of the Week- Feb 5, 2018

ULTRASOUND: Abdomen

Case Author: Ulrike M. Hamper, MD, MBA, Johns Hopkins University

History

32-year old man with HIV infection and AIDS and acute renal failure.

Imaging Findings

Sagittal gray-scale ultrasound image of the right kidney (RK) (A) shows increased renal parenchymal echogenicity and an irregular, hypoechoic perirenal soft-tissue mass. A small hypoechoic liver lesion also is evident. Sagittal color (B) and power (C) Doppler ultrasound images show internal flow in the perirenal soft tissues. Sagittal color Doppler ultrasound image (D) also shows a focal hypoechoic mass in the upper pole of the right kidney.

Perinephric abscess
Perinephric hemorrhage
Perirenal lymphoma
Renal cell carcinoma with liver metastasis

Diagnosis

Perirenal lymphoma

Teaching Points

Renal and perirenal hemorrhage can be caused by blunt or penetrating trauma, rupture of renal cell carcinoma or angiomyolipoma, or intervention such as fine-needle aspiration biopsy. Renal and perirenal hematomas can be hypoechoic, hyperechoic, or heterogeneous. In acute hemorrhage, arterial flow from the lacerated vessel may be seen, but the hematoma itself is avascular at color Doppler ultrasound. Renal involvement is more common with non-Hodgkin lymphoma. Lymphoma is usually hypoechoic at ultrasound. The sonographic appearance of renal lymphoma has different patterns, including focal parenchymal masses, diffuse infiltration, direct invasion from a retroperitoneal mass, and perirenal involvement. Large B-cell lymphoma occurs more commonly in patients with HIV infection or AIDS than in the general population. In this case, fine-needle aspiration biopsy is the next step in management. Perinephric abscess is a complication of pyelonephritis or results from direct extension of a peritoneal or retroperitoneal infection or intervention. Renal abscess tends to be a solitary lesion presenting as a round, thick-walled, hypoechoic complex mass, often with acoustic enhancement and occasionally containing internal gas bubbles. Renal cell carcinoma is a solid lesion at sonography with no predilection for either kidney. Tumors can be hypoechoic, isoechoic, or hyperechoic, most being isoechoic. A familial variety occurs that is multifocal and bilateral.

Schedules and Media