Do Incidental Hyperechoic Renal Lesions Measuring Up to 1 cm Warrant Further Imaging? Outcomes of 161 Lesions

Are There Ultrasound Features to Distinguish Small (<3 cm) Peripheral Renal Angiomyolipomas From Renal Cell Carcinomas?

BACKGROUND

Small echogenic renal masses are usually angiomyolipomas (AMLs), but some renal cell carcinomas (RCCs) can be echogenic and confused with an AML.

OBJECTIVES

This is a study to evaluate any distinguishing demographic and sonographic features of small (<3 cm) peripheral AMLs versus peripheral RCCs.

METHODS

This is a HIPAA-compliant retrospective review of the demographics and ultrasound features of peripheral renal AMLs compared with a group of peripheral RCCs. All AMLs had confirmation of macroscopic fat as noted on thin-cut CT or fat-saturation MRI sequence images. All RCCs were pathologically proven. Statistical analysis was used to compare findings in the two groups.

RESULTS

There were a total of 52 patients with 56 AMLs, compared with 42 patients with 42 RCCs. There were 42 females in the AML group versus 10 females in the RCC group (P < .0001). The AML diameters (15.7 mm × 12.0 mm) were statistically significantly smaller (Plargest  = .0085, Psmallest  < .001) than the diameters of the RCCs (19.9 mm × 18.5 mm). Ultrasound features found to be statistically different between the two groups were the ratio of the largest dimension to the smallest dimension (P < .001), a lobulated versus smooth margin of the AML (26 vs 30) compared with the RCC group (3 vs 39) (P = .0012), and an "unusual" versus a round shape (P < .001) of the AML group (45 vs 11) compared with the RCC group (9 vs 33). In the multivariable model, the patient sex, margin, and mass shape were predictive of AML, with an area under the receiver operating characteristic curve of 0.92.

CONCLUSION

For a small (<3 cm) peripheral echogenic mass in a female patient, a lobulated lesion with an unusual shape is highly predictive of being an AML.

Huge Renal Angiomyolipoma Mimicking a Renal Cell Carcinoma: A Case Report

Renal angiomyolipoma is a benign mesenchymal tumor composing adipose tissue, smooth muscle, and blood vessels. Despite being benign, the tumor sometimes can be aggressive with a locoregional and venous extension. Here, we present a case of a 48-year-old female who presented with a lump in the abdomen for two months, which was initially small and gradually increased in size associated with pain. Ultrasound of abdomen-pelvis showed ill-defined heterogeneous lesion arising from left kidney showing few hypoechoic and calcific focus within it. Contrast-enhanced computed tomography suggested an exophytic mass lesion with a central scar and calcification measuring 13 x 11 cm indicating renal cell carcinoma. Based on the benign nature and being well encapsulated, the patient was taken up for a left radical nephrectomy. However, the final histologic assessment concurred with renal angiomyolipoma.

Etiology of Small Echogenic Renal Masses

OBJECTIVES

There has been controversy on how frequently small echogenic masses are angiomyolipomas (AMLs) versus renal cell carcinoma (RCC) and how best to manage these echogenic masses. We performed this study to determine the etiologies of echogenic renal masses and compare them with prior publications to reach possible management decisions.

METHODS

This is a retrospective chart review of all consecutive renal ultrasound examinations performed at our institution between January 2015 and December 2016, with an ultrasound report finding containing the wording "echogenic" and "mass." This yielded 6462 total examinations. A total of 107 echogenic lesions met inclusion and exclusion criteria with correlative computed tomography, pathology, or long-term (>5 years) follow-up ultrasound. These lesions were stratified into those that were ≤2 cm and those that were >2 cm.

RESULTS

Almost all masses were benign, with the majority (79/107) being AMLs (73.8%); 64 of the 79 (81%) of the AMLs were in female patients. Two of the 107 masses were RCCs, and 1 mass was an oncocytic neoplasm. There were 77 of the masses that were ≤2 cm and these masses were benign except for one lesion of an oncocytic neoplasm. There were 30 of the 107 masses >2 cm, with 2 of the 30 (6.7%) being RCCs.

CONCLUSIONS

Incidental echogenic renal masses are most commonly AMLs. However, some masses may be RCCs. In comparing our results with the prior literature, we feel that small echogenic renal masses ≤1 cm usually require no further evaluation, while masses greater than that size require other imaging.

Pitfalls in Renal Ultrasound

Ultrasound (US) is replete with pitfalls in technique and interpretation, and renal imaging is no exception. Because US of the kidneys is a very common initial and follow-up imaging examination, it is important to be aware of both common and unusual sources of potential error. This essay will review optimal technique and discuss common overcalls, under calls, and misinterpretations with respect to renal size, hydronephrosis, calculi, cysts, masses, and collections.

ACR Appropriateness Criteria® Indeterminate Renal Mass

Renal masses are increasingly detected in asymptomatic individuals as incidental findings. CT and MRI with intravenous contrast and a dedicated multiphase protocol are the mainstays of evaluation for indeterminate renal masses. A single-phase postcontrast dual-energy CT can be useful when a dedicated multiphase renal protocol CT is not available. Contrast-enhanced ultrasound with microbubble agents is a useful alternative for characterizing renal masses, especially for patients in whom iodinated CT contrast or gadolinium-based MRI contrast is contraindicated. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Roles for active surveillance in renal cancer

PURPOSE OF REVIEW

With this review, we describe the most recent advances in active surveillance as well as diagnosis and management of small renal masses (SRMs).

RECENT FINDINGS

We discuss diagnosis, differentiation of solid from cystic lesions, risk prediction and treatment of the SRM. A better understanding of the disease facilitates the use of more conservatory treatments, such as active surveillance. Active surveillance has been increasingly accepted not only for SRM, but also for larger tumors and even metastatic patients. Exiting advances in risk prediction will help us define which patients can be safely managed with active surveillance and which require immediate treatment. Meanwhile, the use of renal tumor biopsies is still an important tool for these cases.

SUMMARY

Active surveillance is an option for many patients with renal masses. Noninvasive methods for diagnosis and risk prediction are being developed, but meanwhile, renal tumor biopsy is a useful tool. A better understanding of the disease increases the number of patients who can undergo active surveillance fully certain of the safety of their management.

The value of surveying the kidneys during pelvic ultrasound examinations

INTRODUCTION

Pelvic ultrasounds are commonly performed for various clinical indications in female patients presenting to the hospital. A survey of the kidneys is routinely included as part of the examination, but there is limited justification for their inclusion in the assessment of every female presenting for a pelvic ultrasound.

METHOD

We examined the utility of surveying the kidney ultrasound during pelvic ultrasonography by reviewing the records of 1009 pelvic ultrasound examinations in 1000 women.

RESULTS

In total, 46 incidental findings were identified, but 91% of these were clinically inconsequential. Only four patients had incidental findings of high clinical priority requiring specialist treatment. Of these, two patients were symptomatic and had urinary tract obstruction due to stones. The other two patients harboured asymptomatic renal cell carcinomas. The overall incidence of renal incidental findings of high clinical priority in asymptomatic patients was two in 1009 examinations (1999 kidneys).

CONCLUSION

Indiscriminate uncritical screening of the kidneys in women presenting for pelvic ultrasound is not evidence-based and represents a low-yield examination with extremely low rate of incidental findings of clinical significance.