What is the interpretation of computed tomography (CT) findings showing a persistently enlarged prostate gland causing mass effect on the bladder base, new mild caliectasis in the left kidney, and a hyperdense renal lesion in the left renal pelvis, potentially causing obstructive effects?

From the Guidelines

The patient requires urgent urological evaluation and contrast-enhanced imaging (CT with contrast or MRI) to properly assess the renal lesion and potential obstruction, given the new findings of mild caliectasis and a more hyperdense lesion in the left renal pelvis, as recommended by recent guidelines such as the ACR Appropriateness Criteria for pretreatment staging of urothelial cancer 1. The CT findings indicate an enlarged prostate gland causing pressure on the bladder base, which is a common finding in conditions like benign prostatic hyperplasia (BPH) or prostate cancer. However, the more concerning issue is the new mild caliectasis in the upper pole of the left kidney, which appears to be related to a persistent renal lesion in the left renal pelvis. This lesion has become more hyperdense compared to previous examinations, suggesting possible progression. The lesion may be causing obstruction, leading to the caliectasis.

• The patient's history of renal tumor/lesion and these new findings warrant immediate attention due to the potential for obstruction and the concerning change in appearance of the lesion.
• Contrast-enhanced imaging is essential for properly evaluating the renal lesion, as it can help distinguish between different types of lesions and assess for potential metastases, as supported by studies such as those by Mirmomen et al 1 and Jinzaki et al 1.
• Assessment of renal function and possible intervention to relieve any obstruction may be necessary to prevent kidney damage, and the prostate enlargement should also be addressed, but the renal findings take priority due to the potential for obstruction and the concerning change in appearance of the lesion.
• Recent studies have shown that CTU has a high diagnostic accuracy in detecting urothelial cancers, with a pooled sensitivity of 96% and a specificity of 99% for identifying UC 1, making it a crucial tool in the evaluation of this patient's condition.

From the Research

CT Findings Interpretation

• The CT findings indicate a persistent marked enlargement of the prostate gland, which is causing a mass effect on the bladder base.
• There is new mild caliectasis in the upper pole of the left kidney, suggesting a possible obstruction or mass effect in this region.
• A persistent renal lesion is present in the left renal pelvis, which appears more hyperdense than in prior exams, but its characterization is limited without IV contrast 2.
• The renal lesion may be causing mass effect and producing caliectasis in the upper pole of the left kidney.

Renal Lesion Characterization

• According to the study on Imaging of Renal Cancer 2, accurate characterization of renal masses is essential to guide management.
• The study suggests that a renal mass CT protocol should include noncontrast, corticomedullary, and nephrographic phases to provide complementary information for diagnosis.
• The use of IV contrast is crucial in characterizing renal masses, and its absence in this case limits the evaluation of the renal lesion 2.
• The Bosniak classification for renal cystic masses, revised in 2019, can help standardize terminology and improve diagnosis, but it is not directly applicable in this case without further imaging or biopsy 2.