If you have cancer of unknown primary origin (CUP), you may have any or all of these symptoms, depending on where in the body the cancer develops.
Swollen lymph nodes. Lymph nodes are tiny, bean-sized organs of the immune system that help to fight infection. CUP commonly spreads to lymph nodes. You may notice swollen or firm lymph nodes. Sometimes, a doctor may notice them during a routine exam. The most typical sites of CUP lymph nodes are on the neck, under the arms, or in the groin.
Pain in the bones. If cancer has spread to the bone, you may have bone pain. The bone may also become weak and may break more easily than usual.
Chest or abdominal pain or fullness. These symptoms may occur if tumors are pressing on internal organs or if the cancer is growing in your liver. If the cancer is growing in the liver, you may also develop bloating and jaundice (yellowing of the skin and whites of the eyes). These symptoms may also occur if cancer grows on the surface of other organs in your abdomen, causing excess fluid to accumulate in your abdomen.
Poor appetite or weight loss, fatigue, or weakness. All of these symptoms can be signs of something other than cancer. Or, they may be signs of cancer that has spread to places such as the bone marrow or digestive tract.
Tumors on the skin. Tumors that begin in organs inside your body can spread to the skin and cause bumps and nodules on the skin. Sometimes, tumors that spread to your skin are the first sign of cancer that has started in an unknown place.
Shortness of breath, persistent cough. If cancer is in the lungs, you may feel short of breath even when doing everyday activities.
Confusion, headache, blurry vision, vomiting, and seizures. These can be signs of a brain lesion, which in rare instances is the only site of a hidden cancer in the body.
It is important to remember that all of these symptoms can be caused by many other medical problems. If you have any of these symptoms, you should see your doctor as soon as possible.