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Cancer of Unknown Primary: Symptoms

One of the first symptoms of CUP may be a swollen lymph node in your neck, underarm, or groin. 

What are the symptoms of cancer of unknown primary?

If you have cancer of unknown primary (CUP), you may have the following symptoms. Your symptoms depend on where in your body the cancer forms.

Swollen lymph nodes

Lymph nodes are tiny, bean-sized organs of the immune system. They help to fight infection. CUP often spreads to lymph nodes. You may notice swollen or firm lymph nodes. Sometimes, a healthcare provider may spot them during a routine checkup. The most common sites of CUP lymph nodes are on your neck, above your collarbone, under your arms, or in your groin.

Pain in your 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 normal.

Chest or stomach pain or fullness

These symptoms may occur if tumors are pressing on internal organs. These symptoms may also happen if the cancer is growing in your liver. This may also cause bloating and yellowing of your skin and whites of your eyes (jaundice). These symptoms may also occur if cancer grows on the surface of other organs in your abdomen. This may cause extra fluid to build up in your abdomen. 

Poor appetite or weight loss, fatigue, or weakness

These symptoms may be signs that cancer has spread to your bone marrow or digestive tract.

Tumors on your skin

Tumors that start in organs inside your body can spread to your skin. This can cause bumps and nodules on your skin. Sometimes, tumors that spread to your skin are the first sign of cancer that has started in an unknown place.

Shortness of breath or a persistent cough

If cancer is in your lungs, you may feel short of breath when doing everyday tasks.


Cancers that start in the digestive tract can cause slow bleeding. This can lead to low red blood cell levels (anemia). Cancer of any type can suppress bone marrow activity. This may result in anemia, too.

Confusion, headache, blurry vision, vomiting, and seizures

These can be signs of a brain lesion. In rare cases, this is the only site of a hidden cancer in the body.

Other symptoms of CUP are also possible. Symptoms depend on where the cancer started. Keep in mind that all of these symptoms can be, and are likely to be, caused by health issues other than cancer.

When to see your healthcare provider

If you have any of these symptoms, see your healthcare provider right away. Many of these symptoms may be caused by other health issues. Only a healthcare provider can tell if you have cancer.

Online Medical Reviewer: Lu Cunningham
Online Medical Reviewer: Richard LoCicero MD
Date Last Reviewed: 2/1/2019
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