Testis

Testis

Embryonal Cell Carcinoma. This is the most common component of mixed testicular tumors, comprising 15-35% of the germ cell tumors. It occurs in the pediatric group (under two years) and in the young adult group, 20-30 years. This tumor is the most aggressive testicular tumor. It metastasizes early and widely via the lymphatic and hematogenous routes. Alpha fetoprotein may or may not be elevated. On ultrasound a hypoechoic mass with areas of increased echogenicity and cystic areas representing necross and hemorrhage may be seen. Invasion of the tunica albuginea should be evaluated. The survival rate is low at 30-35%.

Teratoma. Although the frequency (4-10%) of teratomas is low, it is the second most common testicular tumor in young boys. Generally this tumor is found to be benign in the pediatric group; it may transform into malignancy in adulthood. The serum alpha fetoprotein may be elevated. On ultrasound the texure of the mass is complex with sonolucent and echogenic components. There is often metastases to the lymph nodes, bone, and liver in 30% of the patients within five years.

Choriocarcinoma. This is an uncommon form of germ cell tumor (1-3%). The peak age is the young adult male. The tumor may rapidly metastasize without evidence of chordiocarcinoma in the primary lesion. There is a high incidence of pulmonary involvement. The serum beta HCG is always elevated. On ultrasound a complex echo pattern is shown with hemorrhage, necrosis, and calcifications. The prognosis is not good.

Yolk Sac Tumor. This tumor is the most common germ cell testicular tumors of infancy and childhood. The serum alphafetoprotein is always elevated.

Metastases to Testis. Metastases to the testis is not a common occurrence. In adults metastases from the prostate > lung > kidney > GI tract, bladder, thyroid, melanoma. Metastases is more common than germ cell tumors in males over 50 years of age. In children neuroblastoma is the primary cause for metastases to the testis. Sonographically it usually appears as a solid hypoechoic mass.

Lymphoma / leukemia of Testis. Lymphoma is not very common (6-7% of all testicular tumors) although it is the most common testicular tumor in men over the age of fifty and is found bilaterally in 40% of cases. Sonographically it appears as a diffuse or focal area of decreased echogenicity.