Cancer which starts developing in the testicles is referred to as testicular cancer. Testicles are made of different types of cells and basically has two main functions -  secretion of male hormones like testosterone, and to produce male germ cells required to fertilize female egg cells. Because of these different types of cells, more than one type of testicular cancers may develop and it becomes necessary to distinguish between them.  

Types of Testicular Cancers  

Germ Cell Tumors  

Germ cells are the cells that make sperm. With germ cells being the reason for more than 90% of testicular cancers, tumors from such cells have been categorized into two types :  

• Seminomas  : These cancers are slower than non-seminomas and are further classified into two subtypes – classical seminomas and spermatocytic seminomas. While classical seminomas tend to afflict men between 25-45 years of age, the average age of men positively diagnosed with testicular cancers is 65. 
  
  
• Non-Seminomas : These cancers develop in men who are in their late teens and early 30s. There are 4 subtypes defines under such cancers, namely Embryonal carcinoma, Choriocarcinoma Yolk sac carcinoma and Teratoma. Teratomas are further classified into 3 types :  Mature teratomas, Immature teratomas and Teratomas with somatic malignance. 
  
  Carcinoma In-situ 
  
  Carcinoma in-situ or CIS, is a name given to cancers that start developing as non-invasive forms. In this type of cancer, the cells look abnormal under the microscope but haven't spread to outside of the region yet. The only way to diagnose such cancer is biopsy as it does not cause any general symptoms to show that it has become invasive.  
  
  Stromal Cancers 
  
  Sometimes, cancer may develop in supporting or hormone secreting tissues (stroma). Such cancers are known as stromal cancers and also as gonadal stromal carcinomas. It has two main subtypes – Leydig cell tumor and Sertoli cell tumor.  
  
  Diagnosis of Testicular Cancer 
  
  Diagnosis of testicular cancers generally involve some of the following procedures :  
  
  Ultrasound 
  
  This is often one of the first tests that doctors perform to diagnose testicular carcinomas. Ultrasound uses sound waves to produce images of the patient's internal organs. These tests are easy test and usually involve no use of radiations as well. 
  
  Surgery  
  
  The procedure to take out a testicular tumor or cancer is called radical inguinal orchiectomy. In this method, the doctor makes an incision just above the testicular area and removes the whole tumor along with the testis and the gamete cord. The entire sample is sent to a pathologist who then looks at the samples under a microscope to detect the extent of the cancer. 
  
  Image Testing 
  
  Imaging tests generally use x-rays, sound waves or magnetic fields concepts to generate images of the inside of our body. Imaging tests include PET (positron emission tomography) scan, CT (computed tomography) scan, Bone scan and MRI (magnetic resonance imaging) scan. Imaging tests may done for a number of reasons :  
  
  

• To know the extent to which the cancer has already spread.
  
  
• To know the location of the cancer.
  
  
• To learn if the provided treatment has helped.
  
  
• To look for any signs of carcinoma coming back after the treatment.