In order to perform your self-exam accurately, know what to look for in the event cancer may be present. This self-exam is designed to check for the following symptoms:  A lump within the testicle.  The lump does not have to be large or painful warrant a doctor visit as tumors can begin as small as a pea or a grain of rice.  Testicular Enlargement. This can be of one or both testicles.Note that it is normal for one testicle to hang slightly lower than the other and to be slightly larger than the other. However, if one testicle is larger than the other or has an abnormal shape or hardness, consult a doctor.  Changes in density or texture. Has one testicle become abnormally firm or lumpy? Healthy testicles are completely smooth all over. Note that the testicles are connected to the vas deferens via a small, soft tube at the top called the epididymis. If you feel this while inspecting your testicles, don't be alarmed; this is normal. Find a room where you won't be disturbed and make sure to have a reasonable-sized, (hands-free, if available) mirror. A bathroom mirror or full length mirror can work well. Being able to visually observe an abnormality of the scrotum is an important aspect of the exam and will require removing any clothing currently covering your lower body, including undergarments. Stand in front of the mirror and examine the skin of the scrotum. Are any lumps visible? Is swelling present?  Is there discoloration or anything else that seems out of the ordinary?  Be sure to examine all sides of the scrotum, including the back. Continue to stand and hold the scrotum in both hands with your fingertips touching, making a kind of basket with your fingers. Hold a teste between your thumb and index finger on the same hand. Press gently to check the density and texture of the teste, then gently roll the teste between your thumb and first finger. Do the same to the other teste using the alternate hand. Take your time. Make sure to thoroughly check the entire surface of each testicle. In addition to...

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Write a summary of the previous text in Vietnamese:
Nhận biết triệu chứng. Tìm một chiếc gương và một nơi kín đáo. Quan sát tình trạng da. Sờ tìm chỗ bất thường. Lên lịch khám hằng năm.