Diagnostic Approach and Management of Fatty Liver and Renal Cysts with Flank Pain

Initial Diagnostic Evaluation

The American College of Radiology recommends non-contrast CT scan of the abdomen and pelvis as the gold standard diagnostic approach for patients with flank pain, with sensitivity up to 97% for detecting urolithiasis and other causes of flank pain 1, 2
Ultrasound should be considered as an alternative first-line imaging modality, particularly in patients with radiation concerns, pregnant patients, and those with known renal cysts requiring characterization, with approximately 90% sensitivity and specificity for characterizing cystic liver lesions 2, 3

The key features to characterize renal cysts include the number of lesions and architecture, with complicated and complex cysts potentially presenting with calcifications, septations, mural thickening, debris-containing fluid, hemorrhagic contents, and wall enhancement 3, 4

The initial imaging modality of choice is non-contrast CT, with ultrasound as an alternative, especially for follow-up of known cysts 1, 2, 3, 4
Asymptomatic simple cysts require no follow-up regardless of size, while symptomatic cysts may require percutaneous drainage or surgical intervention 5, 6

Management of fatty liver should focus on weight loss through diet and exercise, control of metabolic risk factors, and avoidance of alcohol 1, 2, 3

Contrast-enhanced CT may obscure stones within the renal collecting system, and delayed development of secondary signs of obstruction may lead to false-negative ultrasound findings 1, 2
Simple renal cysts typically follow an indolent course without significant changes in size over time and rarely require intervention unless symptomatic 5, 6