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Skin cancers cause abnormal cell changes in the skin, usually in the outer layer. Skin cancer makes up fully 75% of the world’s diagnosed cancers. Although most cases of the condition are cured, others, particularly melanoma, can cause death if not treated.


The most serious type of skin cancer is melanoma. Melanoma develops when ultraviolet radiation from sun exposure or tanning beds damages DNA in skin cells triggering mutations, leading to the abnormal multiplication of skin cells and the formation of malignant tumors. The tumors come from melanocytes, or the skin’s pigment-producing cells, found in the basal layer of the skin’s epidermis. Melanoma is different than less dangerous types of skin cancers as it tends to grow downward and if not treated can begin depositing cancerous cells into the bloodstream, where they can then spread throughout the body.


There are some common warning signs of melanoma. When these are detected, it is imperative that you seek help from a dermatologist immediately. Dr. Matsuda and Dr. Sheu in Honolulu can determine the progression of your skin damage, and provide the corresponding treatment.

Warning signs of a potential melanoma include asymmetrical growths on the skin that have uneven borders. Those growths can also display a variety of colors, from certain shades of brown to tan or black. They, however, may also become red, blue, or almost any other color.

The diameter of the growths may be larger than a pencil eraser (¼ of an inch or 6 mm), although they can appear smaller when initially detected. If you notice a growth is evolving in size, shape, elevation, or color, or you have other symptoms like itching, crusting, or bleeding, it could be a dangerous sign and should be checked by a doctor immediately.


The main cause of melanoma is chronic exposure to UVA and UVB rays. People who live in areas that have more sun exposure, such as Hawaii, Australia, and Florida, are more likely to develop this type of skin cancer. Exposure from tanning beds is equally dangerous.


Atypical moles, or dysplastic nevi, can indicate pre-cancerous growth. People with more moles, regardless of type, are at a higher risk for skin cancer. People with fair skin, or those with lighter hair and eye color also have an increased risk for skin cancer. Heredity may be a major factor for the development of melanoma, too. If you have an immediate family member who has had melanoma, then your risk of developing it is 50 percent greater than those without family history. Furthermore, if you have had other non-melanoma skin cancers such as squamous or basal cell carcinoma, you are at an increased risk for developing melanoma.


Surgical removal of the melanoma and some healthy tissue surrounding it is the only treatment for melanoma. In most cases, this procedure may be done on an outpatient basis. In the case of thin melanomas, it is done under local anesthesia. For thicker melanomas, a biopsy of any potentially affected lymph nodes may be recommended by the doctor.


If you possess certain risk factors for skin cancer, the following preventive measures may help you avoid the condition:

  • Avoid the sun when it is at its peak, usually between 10 AM and 2 PM.
  • When outdoors, wear protective gear such as a brimmed hat, sunglasses, long sleeves, and trousers to block out UV exposure.
  • Application of sunblock with a 30 or higher sun protection factor (SPF) is advised.
  • When suspicious skin lesions are detected, consult a physician immediately, especially if you notice abnormality in one of your moles or if you have a family history of skin cancers.
  • Have your moles checked by a dermatologist every year.


Matsuda Dermatology
405 N Kuakini St., Suite 703
Honolulu, HI 96817
Phone: 808-818-8937
Fax: (808) 941-3112

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