A longitudinal sonographic view of the right kidney shows a hyperechoic mass in the upper pole of the kidney (arrow) in this asymptomatic woman.
Differential Diagnosis: Hyperechoic Renal Mass
- Angiomyolipoma (AML)
- Renal cell carcinoma (RCC) (esp. papillary type)
- Most common cause of hyperechoic renal mass = AML
- 20% - 50% of small RCCs (less than 3 cm) are hyperechoic
- Hence, on the basis of echotexture along, ultrasound cannot reliably differentiate an AML from renal cell carcinoma
- US features suggestive of RCC: 1) anechoic rim, 2) cystic area within the mass (intratumoral cyst)
- CT or MRI is warranted to further evaluate a hyperechoic renal mass
Our case: subsequent CT shows fat within the mass, consistent with AML.
1. Yamashita Y, Ueno S, Makita O, et al. Hyperechoic renal tumors: anechoic rim and intratumoral cysts in US differentiattion of renal cell carcinoma from angiomyolipoma. Radiology 1993; 188:179-182.
2. Vikram R, Ng CS, Tamboli P, et al. Papillary renal cell carcinoma: radiologic-pathologic correlation and spectrum of disease. RadioGraphics 2009; 29:741-754.