Testicular cancer is commonly seen in young people. Most cases of testicular cancer tend to be curable, especially if diagnosed in early stages. So, it's important to know the most significant clinical signs of testicular cancer; they include the following: 

1. Palpable lump in the scrotum: it's the most common presenting sign of testicular cancer in which the patient accidentally discovers an abnormal mass inside the scrotum. 

2. Marked changes in the size and consistency of the testes: this occurs due to decreased production of testosterone hormone. 

3. Feeling of pressure or heaviness inside the scrotum by the effect of the newly developed lump. 

4. Leg swelling: it occurs when the tumor spreads to the adjacent lymph nodes, which probably causes constriction of blood flow to the leg veins, which in turn leads to leg swelling. 

5. Shortness of breathing and low back pain: development of these symptoms means spread of tumor to the abdominal lymph nodes as well as the lungs. 

6. Gynecomastia and breast tenderness: it means overgrowth of the breast tissue by the effect of increased levels of human chorionic gonadotropin (HCG) hormone, which is secreted by the tumor. This clinical sign is relatively rare, but it should be in consideration in assessment.