Contrast-enhanced ultrasound in the diagnosis of a solitary neck mass: a case report of metastatic seminoma.

Seminoma accounting for approximately 98% of malignant testicular tumours and it typically presents as a painless, palpable solid mass in the testis. Seminomas presenting only as a solitary neck mass are very rare. This case report describes a previously healthy 35-year-old male that presented with a 3-month history of the incidental discovery of a mass in his right neck. He had no testicular symptoms. He underwent neck ultrasound, contrast-enhanced ultrasound, computed tomography and positron emission tomography. Serum human chorionic gonadotropin (3.90 mIU/ml) was raised and alpha-fetoprotein (3.79 ng/ml) was within normal limits. Clinical examination and imaging examinations did not find any suspicious signs of testicular cancer. Biopsy from the neck mass confirmed the diagnosis of metastatic seminoma. The case report presents the ultrasound and contrast-enhanced ultrasound characteristics of seminoma and provides an update of the literature regarding this very rare metastatic site for seminomas.