What Is Melanoma?

Types of Melanoma
- Superficial Spreading Melanoma This is the most common type of melanoma. It typically grows across the top layer of skin and may penetrate deeper, especially on the torso or legs.
- Lentigo Maligna This type of melanoma usually develops slowly on the outermost layer of chronically sun-damaged skin, particularly the face and neck of older adults. When it becomes invasive, it is called lentigo maligna melanoma.
- Nodular Melanoma This is the most aggressive form of melanoma. It occurs in about 10 to 15 percent of cases and has usually begun to spread to deeper tissue when symptoms start or when it's diagnosed.
- Acral Lentiginous This generally appears as a dark mark underneath toenails or fingernails, on the sole of the foot, or on the palm of the hand.
Non-Skin Melanomas
Melanomas can develop in any part of your body with melanocytes, a type of cell that creates melanin.
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Holly Rowe — Skin Spots and Taking a Melanoma Diagnosis Seriously
Signs and Symptoms of Melanoma
The most important sign of melanoma is a new spot on your skin or a spot that is changing in shape, size, or color.
- A is for asymmetry. One half of a mole doesn't match the other.
- B is for border. The border is irregular.
- C is for color. The color isn't uniform and may contain different shades of brown, black, pink, red, white, or blue.
- D is for diameter. The spot is larger than 6 millimeters across (although some melanomas can be smaller).
- E is for evolving. The mole is changing in size, shape, or color.
Melanoma In the Eye: Can It Happen?
Causes of and Risk Factors for Melanoma
Melanoma occurs when melanocytes (cells that give your skin its color) experience DNA changes that lead to cancerous growth. This growth leads to tumors, or melanomas.
It’s not clear exactly what causes melanoma, but experts agree that UV radiation from sunlight and indoor tanning is a major preventable risk factor for cutaneous melanoma. Genetics and other risk factors may also play a role.
- Family history of melanoma
- One or more severe sunburns
- More than 50 typical moles
- One or more atypical moles
- Weakened immune system
How Is Melanoma Diagnosed?
Staging Melanoma
If you receive a diagnosis of melanoma, the next step is to determine the extent of the cancer, or stage.
Staging melanoma is a complex, vitally important process that both indicates how severe the cancer is and what kinds of treatment could most help.
Doctors stage the severity of melanoma using the numbers 0 through 4. The higher the stage, the more advanced the cancer.
- Tumor (T) Doctors measure the melanoma under a microscope with a special tool to determine its thickness and whether there is ulceration (when the skin is broken due to the tumor). In general, the thicker the melanoma, the more serious the disease.
- Node (N) If there's a risk that the cancer has spread to nearby lymph nodes or surrounding tissues, doctors may remove them to test for cancer cells.
- Metastasis (M) If doctors suspect that the cancer may have spread, they might use imaging tests, such as an X-ray, MRI, or CT scan, to look for signs of cancer in other areas of the body.
Treatment Options for Melanoma
Surgery
If the melanoma has spread deeper into the skin or to nearby lymph nodes, you may have other tests or treatments to make sure all the cancer cells are killed.
Cancer Therapies
- Radiation therapy
- Immunotherapy
- Targeted therapy
- Chemotherapy
In August 2026, the U.S. Food and Drug Administration approved Tudriqev (vusolimogene oderparepvec), a new type of oncolytic virus therapy for people with advanced skin cancer that no longer responds to PD-1 blocking treatments (a common type of immunotherapy).

Lifestyle Changes and Prevention of Melanoma
- Wear protective clothing. If you’re spending time outside, you can protect yourself by wearing a broad-brimmed hat, UV-protective glasses, and garments that cover as much skin as possible. Dark, tightly woven clothes are also good UV shields.
- Wear sunscreen year-round. Wear a broad-spectrum sunscreen with SPF 30 or higher, even on cloudy days. Remember to reapply regularly and after sweating or swimming.
- Avoid tanning beds and lamps. Tanning beds and lamps give off UV light, which can increase your risk of melanoma.
- Get regular skin exams from a dermatologist. Regular skin exams can help detect cancer early, improving your chance of successful treatment.
- Do self-exams to check for skin changes. Regular self-exams will help familiarize you with all the moles, spots, and other growths on your body. This makes it easier to spot any changes in color, size, shape, or other traits that may indicate cancer.
FAQ
Resources We Trust
- Mayo Clinic: Melanoma Pictures to Help Identify Skin Cancer
- Cleveland Clinic: Is That Mole Cancerous?
- The American Melanoma Foundation: Melanoma Risk Factors
- Melanoma Research Alliance: Just Diagnosed With Melanoma
- American Cancer Society: Melanoma Skin Cancer
- Melanoma. Skin Cancer Foundation. September 2026.
- Five-Year Survival Rates. National Cancer Institute. September 10, 2026.
- Porter D. What Is Ocular Melanoma? American Academy of Ophthalmology. January 13, 2026.
- Types of Melanoma. City of Hope. May 27, 2022.
- Signs and Symptoms of Melanoma Skin Cancer. American Cancer Society. August 12, 2026.
- Melanoma: Symptoms and Causes. Mayo Clinic. December 30, 2023.
- Understanding Melanoma Staging. Melanoma Research Alliance.
- Early Detection, Diagnosis, and Staging of Melanoma Skin Cancer. American Cancer Society. August 12, 2026.
- FDA Approves New Engineered Viral Immunotherapy for Patients with Treatment-Resistant Advanced Melanoma. U.S. Food and Drug Administration. August 6, 2026.
- Okobi OE et al. Trends in Melanoma Incidence, Prevalence, Stage at Diagnosis, and Survival: An Analysis of the United States Cancer Statistics (USCS) Database. Cureus. October 2, 2024.

Blair Murphy-Rose, MD
Medical Reviewer
Blair Murphy-Rose, MD, is a board-certified dermatologist in New York City and the founder of Skincare Junkie. She is an accomplished cosmetic, medical, and surgical dermatologist,...

Pamela Kaufman
Author
Pamela Kaufman assigns and edits stories about infectious diseases and general health topics and strategizes on news coverage. She began her journalism career as a junior editor on...