Ultrasonographic features of testicular metastasis from renal clear cell carcinoma that mimics a seminoma: A case report

RATIONALE: Testicular metastases from renal cell carcinoma (RCC) are extremely rare. To the best of our knowledge, only 35 cases have been described in the literatures. PATIENT CONCERNS: A 64-year-old male presented to our urology clinic for a palpable painless mass on his right side of the scrotum by self-examination 1 week ago, with a general abdominal ultrasonographic report showing a mass in his right kidney. DIAGNOSES AND INTERVENTIONS: Scrotal B-mode ultrasound revealed a 15 × 13 × 15 mm well-defined round homogenously hypoechoic nodule with a halo at the upper pole of the right testis. Color Doppler and spectral Doppler ultrasound detected abundant intranodular and perinodular blood flow signals including both arteries and veins. Malignancy was suspected. Abdominal contrast-enhanced computed tomography identified an irregular tumor in the posterior side of the right kidney, highly suspicious for renal carcinoma. The patient received right radical nephrectomy and right partial orchiectomy. Histologically, the right renal mass was diagnosed as RCC, clear cell type, grade 2. As to the right testicular mass, a metastasis from renal clear cell carcinoma was confirmed. OUTCOMES: The patient has lived with no recurrence for at least 17 months without adjuvant therapy. LESSONS: In the case, we focus on the ultrasonographic features of the testicular metastasis from RCC. Ultrasound could provide initial and helpful information for diagnosis. When finding a mass in the testicle on the ultrasound, although most of them are primary, it is important to know whether the patient has tumor history from other parts of the body. A halo may be a special feature for metastases. Contrast-enhanced ultrasound (CEUS) and ultrasonic elastography could provide more information for differential diagnoses.