Skin cancer that has spread beyond its original site typically announces itself through a combination of physical changes you can see or feel and symptoms that seem unrelated to your skin. The most common first sign is a hard or swollen lymph node near the original cancer, but spread to distant organs like the lungs, liver, brain, or bones each produces its own distinct warning signs. Knowing what to watch for depends partly on which type of skin cancer you have, since melanoma, squamous cell carcinoma, and basal cell carcinoma behave very differently once they start to spread.
The First Physical Signs of Spread
The earliest clue that skin cancer has moved beyond the original tumor is often a change in nearby lymph nodes. Lymph nodes that have become hard, swollen, or fixed in place (rather than soft and movable) suggest cancer cells have reached them. The most relevant nodes depend on where your original skin cancer was: a melanoma on your leg might affect nodes in your groin, while one on your face or scalp could involve nodes in your neck.
Another early sign is the appearance of small, firm lumps under the skin near the original cancer site. These subcutaneous nodules can be the first evidence of cancer cells traveling through the bloodstream, and they sometimes show up before any internal organ involvement is detected. Satellite lesions, which are tiny new tumors that appear within a few centimeters of the primary site, also indicate regional spread.
Symptoms That Suggest Distant Spread
When skin cancer reaches distant organs, the symptoms depend on where it lands. The most common destinations for melanoma are the lymph nodes, lungs, brain, liver, and bones.
- Lungs: A persistent cough, shortness of breath, or chest pain. Lung involvement is the most common cause of death in metastatic melanoma, typically through progressive respiratory failure.
- Bones: Deep, continuous pain that people often describe as gnawing. Back pain that worsens despite rest is a classic red flag for bone metastases.
- Liver: Poor appetite, unexplained weight loss, and sometimes pain or fullness in the upper right abdomen.
- Brain: Headaches, seizures, vision changes, or new neurological symptoms like weakness on one side of the body or difficulty with balance.
- Gastrointestinal tract: Melanoma can spread to the small intestine, large intestine, or stomach. These metastases are often silent for a long time, sometimes mimicking the symptoms of ordinary stomach irritation. When they progress, they can cause intestinal obstruction or bleeding.
Some symptoms cut across all sites: unexplained weight loss, persistent fatigue, and feeling generally unwell without a clear reason. These systemic signs often reflect the body’s response to cancer growing in places it shouldn’t be, and they can appear before any organ-specific symptoms become obvious.
How Doctors Test for Spread
If your doctor suspects your skin cancer may have spread, the workup typically starts with imaging and may include a biopsy of suspicious lymph nodes.
Sentinel Lymph Node Biopsy
For melanoma, the most important early test is a sentinel lymph node biopsy. This procedure identifies the first lymph node that drains the area around your tumor, removes it, and checks it for cancer cells under a microscope. It’s the most reliable way to determine whether melanoma has reached the lymphatic system before nodes are large enough to feel on an exam. This biopsy is typically recommended for melanomas that are thicker or have other high-risk features.
Imaging Scans
For detecting spread to distant organs, PET-CT is the most accurate imaging tool available. A large meta-analysis found that PET-CT detected distant metastases with about 80% sensitivity and 87% specificity, outperforming both standard CT scans and PET scans used alone. CT alone caught only about 51% of distant metastases. For checking lymph nodes specifically, ultrasound performs best.
Your doctor will choose imaging based on your risk level and symptoms. Someone with a thin, early-stage melanoma and no symptoms rarely needs full-body scans. Someone with a thicker tumor or concerning symptoms will likely get PET-CT to check the chest, abdomen, pelvis, and brain.
Blood Tests
A blood test measuring lactate dehydrogenase (LDH), an enzyme released when cells are damaged, plays a specific role in melanoma staging. Elevated LDH levels in someone with melanoma suggest the cancer may have spread and are associated with worse outcomes. In studies, every increase of 100 units per liter in baseline LDH raised the risk of death by roughly 44 to 49%. LDH isn’t precise enough to guide treatment decisions on its own, but it adds useful information alongside imaging results.
How Staging Reflects Spread
Melanoma staging uses a system that directly maps to how far the cancer has traveled. Stage III means the cancer has reached nearby lymph nodes or produced satellite tumors between the original site and the nearest lymph node basin. Stage IV means it has spread to distant organs. Within Stage IV, the specific designation depends on where the metastases are: spread to the central nervous system gets its own category because it carries a different prognosis than spread to, say, the lungs or liver.
The staging system also factors in that LDH blood test. Two patients with the same pattern of organ involvement will be staged differently if one has elevated LDH and the other doesn’t, because elevated LDH consistently predicts a more aggressive course.
Differences by Skin Cancer Type
Not all skin cancers carry the same risk of spreading. Melanoma is by far the most likely to metastasize, which is why most of the screening and staging infrastructure exists around it.
Squamous cell carcinoma of the skin spreads less frequently, but certain features make it far more dangerous. Tumors larger than 2 centimeters in diameter, deeper than 4 millimeters, located on the lip or ear, poorly differentiated under the microscope, growing along nerves, or occurring in someone with a suppressed immune system all carry elevated metastatic risk. Rapidly growing tumors and those that recur after treatment are also red flags. If you’ve had a squamous cell carcinoma removed and notice new hard lumps near the surgical site, swollen lymph nodes, or neurological symptoms like tingling or numbness in the area, these warrant prompt evaluation.
Basal cell carcinoma almost never spreads. Metastasis rates range from 0.0028% to 0.55%, making it an extraordinarily rare event. When it does happen, it follows the same pattern as other skin cancers: regional lymph nodes first, then lungs and bones. But for the vast majority of people with basal cell carcinoma, spread is not a realistic concern.
Monitoring Yourself After Treatment
If you’ve been treated for skin cancer, monthly self-exams are one of the most practical things you can do. Stand in front of a full-length mirror in good lighting and use a handheld mirror or a partner’s help to check your back and scalp. You’re looking for new or expanding moles, sores that bleed or won’t heal after several weeks, rough red patches that crust or bleed, and moles with irregular borders or multiple colors.
Beyond the skin itself, pay attention to your body more broadly. Persistent fatigue, unexplained weight loss, new lumps under the skin, bone pain that doesn’t resolve, or any of the organ-specific symptoms listed above are worth reporting to your care team. Catching spread early, before it becomes symptomatic enough to be obvious, is one of the strongest advantages in treatment. Your follow-up schedule with your dermatologist or oncologist exists precisely to catch these changes at their most treatable stage.