Testis cancer is suspected with the finding of any mass involving the body of the testicle, although, GCTs are found outside of the testis in about 10% of cases. Classically, these testicular masses are described as painless, firm lesions ranging in size from millimeters to a few centimeters. However, it is common for there to be some degree of pain or swelling in the involved testicle or other associated testicular structures, possibly caused by bleeding or inflammation within the tumor. Other, non-neoplastic processes can also cause these findings, necessitating further tests to confirm the diagnosis before considering surgery. A full examination including lymph node and rectal exam should be performed as well as urine and, when indicated, blood tests. A scrotal ultrasound is a safe and non-invasive test often used to determine the anatomic relationship between the mass and the testis as well as to identify components of fluid and blood flow.

Diagnosis of a testicular GCT requires microscopic tissue examination by a pathologist. Tissue is obtained by surgical removal of the involved testis (inguinal orchidectomy) through a groin incision using an approach similar to performing a hernia repair. GCT can spread to other parts of the body through the lymphatic drainage from the testicle and so further imaging tests are performed including chest x-ray and computed tomography (CT scan) of the abdomen and pelvis to look for evidence of tumor growth in the lymph nodes or other sites. Further treatment largely depends on the type of GCT found by the pathologist and the results of imaging tests for staging. Germ cell tumors of the testis are divided into two broad categories based on microscopic findings: seminoma and nonseminomatous tumors. Seminoma is the most common type of testis cancer, occurring in roughly 50% of all cases. They are very sensitive to both radiation and chemotherapy treatments and considered highly curable cancers with excellent long-term disease free survival when treated appropriately.

The group of nonseminomatous tumors includes embryonal carcinoma, choriocarcinoma, yolk sac tumor, and teratoma. Tumors may be composed of a mix of these different cell types, including seminoma, and are treated as nonseminomatous cancer. These tumors are somewhat more difficult to treat than pure seminoma due to their more aggressive biology and diminished response to chemotherapy.

SERUM MARKERS
Some GCTs release products into the blood stream that can be detected in the laboratory. These products, referred to as tumor markers, include alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG), and lactate dehydrogenase (LDH). Unfortunately, these markers are not always present in the blood of patients with GCT and are not reliable as a screening test for cancer. When markers are detectable, they provide clues in diagnosing the type of GCT present and in following the response to treatment. Higher marker values are correlated with greater extent of disease. A summary of these markers and their expression by different tumor cell types is provided in table 1.

Table 1.