The Signs and Symptoms of 5 Rare Forms of Skin Cancer

Skin cancer is a very common condition in the United States. In fact, 1 out of 5 Americans will likely develop skin cancer in their lifetimes. More common types of skin cancer are well known, like basal cell carcinoma, squamous cell carcinoma, and melanoma.1 But there are other, rarer, types of skin cancer to be aware of. And it is important to recognize their signs and symptoms. This way, you know what to look for and when to follow-up with your doctor.

Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, but aggressive type of skin cancer. About 2,500 Americans are diagnosed each year. Even though this form of skin cancer is rare, it spreads very rapidly. So, early detection and removal is critical.1,2

What to look for

MCC tumors are usually found on sun-exposed areas, such as the head, neck, or eyelids. These tumors look like firm, shiny, or pearly nodules and are typically painless. They can be skin-colored, red, purple, or bluish-red. The size can vary, but the average size is usually about the diameter of a dime. Be aware of the following warning signs:1,2

A: ASYMPTOMATIC lesion, not painful or tender
E: Lesion is EXPANDING rapidly
I: You are IMMUNOsuppressed
O: You are OLDER than 50
U: The lesion appears on UV-exposed skin

How to diagnose

MCC can be difficult to diagnose and is often undetectable. This can lead to delayed medical treatment for the condition. The appearance of MCC tumors can vary, so be sure to check your skin regularly and
report any odd-looking skin lesions to your doctor.2

Dermatofibrosarcoma protuberans

Dermatofibrosarcoma protuberans (DFSP) is another rare form of skin cancer that first develops in the middle layer of the skin. This type of skin cancer rarely spreads, so it has a high rate of survival. DFSP affects about 1,000 Americans each year.3,4

What to look for

Because DFSP begins in the middle layer of the skin and grows so slowly, it can take a while to notice the signs. It first appears as a pimple-like growth or rough patch of skin. The growths are usually painless and there is little change over time. As it grows, it can become sore, cracked, or hard.5

How to diagnose

A biopsy is the only way to diagnose DFSP. Your doctor will remove some of the tumor and examine it under a miscroscrope.6

Sebaceous gland carcinoma

Sebaceous gland carcinoma (SGC) is another aggressive form of skin cancer that can spread quickly. It is another rare form of skin cancer. Still, it is considered the third most common eyelid cancer.7,8

What to look for

SGCs mostly develop on a person’s eyelid. If you have SGC, you may notice:9

  • A slow-growing, yellowish, firm, painless lump
  • Thickening of the eyelid
  • Yellow or reddish crust
  • A growth that looks like a pimple on the eyelid
  • A growth on the eyelid that bleeds
  • A growth or sore on the eyelid that will not heal or keeps coming back

How to diagnose

There are certain risk factors that make SGC more likely. If you have signs and symptoms, your doctor will probably ask if you have or have had:10

SGC is diagnosed through a skin exam, lymph node exam, and possibly a biopsy.10

Kaposi's sarcoma

Kaposi's sarcoma (KS) is caused by the herpes virus. It typically appears in people with weakened immune systems. It is most common in people with Acquired Immunodeficiency Syndrome (AIDS).11

What to look for

Symptoms of KS usually appear as red or purple patches on the skin and mouth. Visible patches on the skin can look like bruises. The patches can spread to inside parts of the body, like the lungs, liver, or digestive system. This usually only occurs in patients with AIDS.11

How to diagnose

If your doctor suspects KC, he or she will probably ask if you have AIDS or another immune system disease. Since lesions can spread to organs in the body, other symptoms might be looked for, like coughing, shortness of breath, wheezing, nausea, vomiting, or abdominal pain. But these symptoms do not occur until very advanced stages of the disease. A biopsy can also confirm KS.11

Cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is actually a rare type of blood cancer that appears on the skin. It grows in people’s T-cells in the blood, and most T-cells are found on the skin. There are two types of CTCL: Mycosis fungoides and Sézary syndrome. Mycosis fungoides is more common and is a slowly progressing disease. Sézary syndrome is aggressive and spreads quickly.12

What to look for

CTCL often looks like a rash, or like eczema or psoriasis. Skin can become red, sore, itchy, or swollen. These skin patches usually develop on areas of the body with little exposure to the sun.12

How to diagnose

CTCL is difficult to diagnose because it is often mistaken for eczema. If eczema treatment does not help, a dermatologist should be involved to examine and test for CTCL.12


Though rare, it is important to be aware of these types of skin cancer. You should regularly examine your skin for any unusual marks or bumps. And anything suspicious should be checked by your doctor immediately.

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