Ultrasound in diagnosis of intrascrotal metastasis of Wilms' tumor: first case report of a Chinese boy and review of the literature.

A 31-month-old boy with Wilms' tumor (WT), which primarily had originated from the left kidney, was treated with nephrectomy and adjuvant chemotherapy. 2 months after nephrectomy, a left scrotal mass was found at routine follow-up. High-frequency sonography examination revealed an enlarged left testis with a heterogeneous texture and a hypoechoic solid mass in the left scrotum. Moreover, hypervascular signals presented in both the left testis and the mass on color Doppler flow imaging. Left orchiectomy was performed for suspected intrascrotal metastasis of WT, which was confirmed by histopathology examination. This was the first case of intrascrotal metastasis of WT reported in China with a detailed ultrasound description. Meanwhile, this study also reviewed the comparable diagnostic methods of intrascrotal metastasis of WT found in the English literature.