Melanoma is a type of skin cancer that originates in the melanocytes, the cells responsible for producing skin pigment. When melanoma progresses beyond its original site and travels to other parts of the body, it is termed metastatic melanoma or Stage IV disease. This spread occurs when cancer cells break away from the primary tumor and move through the body’s lymphatic system or bloodstream. Recognizing the signs of this progression is important because symptoms often depend on the specific location where the cancer has settled and begun to grow. Understanding these location-specific changes is key for prompt medical evaluation and treatment.
Symptoms of Regional Spread
The first stage of spread often involves the lymphatic system closest to the original skin tumor. Symptoms typically center on the regional lymph nodes, which are small, bean-shaped glands that filter lymph fluid.
The lymph nodes in the area draining the primary tumor, such as the armpit, groin, or neck, may feel swollen, firm, or tender. These nodes can sometimes be felt as hard, enlarged lumps under the skin. The swelling can occasionally cause discomfort or reduced mobility in nearby joints, depending on the lymph node group affected.
Beyond the lymph nodes, melanoma can also spread to the skin and underlying soft tissue between the primary tumor site and the regional lymph nodes. This is known as in-transit metastasis, which appears as new, small, dark nodules or lumps on the skin. These lumps represent clusters of melanoma cells that have settled in the lymph channels.
Symptoms of Distant Visceral Spread
Once melanoma has spread beyond the regional lymph nodes, it frequently travels to distant internal organs, a process called visceral metastasis. The lungs, liver, and gastrointestinal tract are among the most common sites for this distant spread.
Symptoms arising from lung metastasis often include a persistent cough that does not resolve, or increased shortness of breath. Lung involvement may also cause discomfort or pain in the chest or result in coughing up blood.
Liver metastasis typically presents with symptoms related to impaired liver function or the physical presence of tumor masses. This can manifest as pain or tenderness in the upper right part of the abdomen. A person may also experience jaundice (a yellowing of the skin and eyes), or feel full quickly after eating only a small amount of food.
Melanoma spread to the gastrointestinal tract can cause unexplained abdominal pain, changes in bowel habits such as chronic diarrhea or constipation, or symptoms of obstruction. Bleeding is also a possibility, which may show up as blood in the stool or vomiting blood.
Symptoms Affecting the Nervous System
Metastasis to the central nervous system, particularly the brain and spinal cord, is a significant concern with advanced melanoma. The symptoms that develop are neurological and vary based on the size and location of the tumor deposits.
Severe or persistent headaches are a frequent complaint, sometimes worse in the morning, which can be accompanied by nausea and vomiting. The presence of tumors in the brain can disrupt normal electrical activity, leading to seizures or convulsions. Other signs of brain involvement include confusion, cognitive dysfunction, changes in personality, dizziness, vision problems, or weakness and numbness on one side of the body.
If the cancer spreads to the bones of the spine, it can compress the spinal cord, leading to malignant spinal cord compression. Symptoms of this compression include back or neck pain, muscle weakness, numbness in the limbs, or difficulty controlling bladder or bowel functions. Any sudden onset of these neurological changes requires immediate medical attention.
Systemic Symptoms and Bone Involvement
Advanced melanoma can cause general, non-localized symptoms that affect the entire body. These systemic symptoms include profound fatigue that is not relieved by rest. A person may also experience a loss of appetite, which can lead to unexplained weight loss. Less common systemic signs include fever or chills that occur without an identifiable infection.
Melanoma may spread to the skeletal system, causing bone metastasis. Bone involvement frequently causes pain in the affected area, and this is often the first symptom noticed.
The cancerous tumors weaken the bone structure, increasing the likelihood of fractures from minor trauma, known as pathological fractures. The spine is a common site for bone metastasis, and tumors here can cause localized pain and potential swelling.