The public health message for melanoma is to look for a change in a mole, and some recite the ABCD’s of melanoma. But there are other types of melanoma that exhibit themselves in a different way. Though rare, they can be missed by a physician and discovered late in progression making them riskier than cutaneous melanoma.
Sometimes the first sign of melanoma is not on the outside of the body at all. Symptoms may result in a scan that finds a tumor in the lung or other body organ. There was no mole or changing lesion that the patient remembers. This is referred to as an unknown primary. It is speculated that at one time there was a mole or lesion that changed into melanoma, then regressed back into the body to seed itself within the body.
Another form of melanoma starts within the body but only in places that are mucous membranes, i.e. the mouth, rectum, vagina etc. hence it is called mucosal melanoma. Sometimes a vaginal melanoma can be classified as cutaneous though, so it is important to determine that distinction on the pathology report. The C-Kit mutation is sometimes found with mucosal melanoma and opens up the opportunity for other treatment regimens.
Some of us worry if we see a dark streak in our fingernail or toenail. What we may have heard about is Acral Lentiginous melanoma or Subungual melanoma, the term for acral in a nail bed. This rare form of melanoma occurs more often in people of color as well as white people and is rare, less than 7% of the population might present with this disease. It shows up on the sole of the foot and the palm of the hands as well. A biopsy will provide the evidence needed to know if you have acral or cutaneous.
Ocular melanoma or Uveal Melanoma starts in the inner third layer of the eye. There is no known cause of this disease. It is rare also in occurrence and should be looked for in an annual eye exam by an ophthalmologist. A good source to read about ocular melanoma is: http://www.cancer.gov/cancertopics/pdq/treatment/intraocularmelanoma/Patient/page1.
One more type of melanoma sometimes missed is amelanotic melanoma. This appears as a flesh colored or pinkish mole or lesion. Because it doesn’t fit the black raised mole description, it too can be dismissed as nothing to worry about and then it can progress.
Don’t forget you know your body better than anyone and should you have a symptom that worries get it checked and insist on a biopsy or other definitive test. Trust your intuition about your body! Sometimes melanoma appears differently than you’d expect.