- The right kidney is markedly enlarged at 8.74 cm. Normal feline renal length is up to about 4.5 cm. The right kidney has mild renal pelvic dilation (green arrow), with an irregular subcapsular hypoechoic rim (orange arrow). Renal architecture is poorly defined and disorganized.
- The left kidney is moderately enlarged (5 cm), with mildly irregular renal cortex, mild pelvic dilation (green arrow), and a hypoechoic subcapsular rim (orange arrow).
A fine needle aspirate was obtained from the right kidney. The cytologic diagnosis was renal lymphosarcoma. Although the left kidney was not sampled, the lymphoma is likely bilateral.
Renal lymphosarcoma typically results in enlarged, hyperechoic kidneys, often with abnormal architecture due to neoplastic infiltration. The hypoechoic subcapsular rim is frequently seen with renal lymphoma.