Nonseminomatous Germ Cell Tumour

testicular tumour

This 31 year-old patient presented with scrotal pain. An ultrasound was performed for a clinical suspicion of epididymo-orchitis. A mass is shown in the testis, with a heterogeneous echogenicity, and small cystic areas. The serum α-fetoprotein and β-human chorionic gonadotropin were both elevated. The findings are in keeping with nonseminomatous germ cell tumour.

NSGCT occur in younger patients than seminoma, with peak incidence in late teens to twenties. They tend to be more aggressive than seminomas, and frequently metastasise. The sonographic appearance is different to seminomas, being more heterogeneous, and sometimes containing cystic areas or areas of calcification.

Mixed germ cell tumour is the most common type of NSGCT, accounting for 40% of all germ cell tumours. The most common combination is teratoma and embryonal cell carcinoma. Pure teratomas account for 5-10% of germ cell tumours, and may be mature, immature or ‘teratoma with malignant transformation’. Teratoma is a common tumour type in infants and young children, where it is typically mature and benign. In adults, teratoma is typically malignant. Other tumour types, including pure embryonal cell carcinoma and pure choriocarcinoma, are rare.

Testicular microlithiasis is a risk factor for germ-cell tumour. The magnitude of the risk may be lower than previously thought (estimated to be 5-10%, rather than 30-40%)3.

References:
1. Rumack CM, Wilson SR, Charboneau JW. Diagnostic Ultrasound 3rd edition. Elsevier Mosby 2005
2. Ueno T, et al. Spectrum of Germ Cell Tumors: From Head to Toe. RadioGraphics 2004;24:387-404
3. Middleton WD, Teefey SA, Santillan CS. Testicular Microlithiasis: Prospective Analysis of Prevalence and Associated Tumor. Radiology 2002;224:425-428

Credit: Dr Laughlin Dawes