Mucosal Melanoma

Last Modified: May 7, 2006

Dear OncoLink "Ask The Experts,"

My friend had a mole removed 2 years ago and was told it was one step away from melanoma. She had 4 surgeries until clear margins were obtained. She was told yesterday that she had melanoma of the colon -had several scans and this was the only area that looked hot. She will have a PET scan done soon. How rare is this? How will it be treated? Is it stage 4? or 2?

Suzanne M. McGettigan, MSN, CRNP, AOCN, Board Certified Adult Nurse Practitioner and a Certified Oncology Advanced Practice Nurse, responds:

Although it does not sound from your description that the lesion removed from the skin was an actual melanoma, it is certainly a possibility that this was the original source. We often will get the pathology slides reviewed in a situation such as this just to be more certain.

Melanoma is considered stage II as long as it is confined to the skin. It is considered Stage III if it has traveled through the lymph system, but remains confined to the local area. This would mean that the melanoma has not traveled outside the regional lymph nodes. Once it has traveled beyond the regional lymph nodes or into another organ, it is considered Stage IV.

Additionally, while most melanomas do occur originally in the skin, they also can originate in the mucosa, which includes the mucosa of the large intestine, esophagus, other mucous membranes (like the nose and mouth), female genitals, and urinary tract. Mucosal melanomas are rare in the U.S., accounting for about 1% of all melanoma cases (this varies in other countries). The cause is unknown, since sun exposure obviously does not play a part. Smoking has been thought to play a role in cases found in the head and neck.

The stage depends on whether this is a new primary lesion (could still be early stage), or if the original skin lesion had spread to this area (which would be stage IV).

It also sounds like the melanoma is confined to the single lesion in the intestine. This is very encouraging, although a PET scan is still pending for confirmation. Primary treatment is surgery to remove the lesion. Other treatments will focus on treating the whole body for any microscopic disease, and may include chemotherapy and/or immunotherapy. Commonly used agents include: cisplatin, DTIC, interferon, and IL-2. There may be clinical trials available as well.