What are the Types of Melanoma?
acral lentiginous. Other subtypes, such as desmoplastic and amelanotic melanoma, also exist but are rare.
The
Ocular Melanoma
After cutaneous, the second most common type of melanoma is ocular melanoma. Just as in cutaneous melanoma, ocular melanoma develops when melanocytes become cancerous and mutate, but instead of being on the skin, these melanocytes are in and around the eye. Read more about ocular melanoma here.
Mucosal Melanoma
Mucosal melanomas develop in the mucous membranes, such the sinuses, nasal passages, oral cavity, vagina, and anus. Mucosal tissues contain melanocytes just as skin does, and those melanocytes can become cancerous. Mucosal melanomas are rare, accounting for only about one percent of all cases of melanoma, but they tend to be more aggressive and have less favorable prognoses compared to cutaneous melanoma. There is currently no standard for staging or treating mucosal melanoma. Researchers have not been able to identify any risk factors: Neither UV exposure nor family history seems to play a role. Read more about mucosal melanoma here.
Melanomas With Unknown Primary (MUP)
In rare cases, melanoma is found to have spread to lymph nodes or organs, but the original tumor site is unknown. When this type of melanoma occurs, it is called melanoma of unknown primary (MUP). Only about 3% of melanomas are MUP.
Current hypotheses suggest that most of these melanomas originate on the skin and arise from:
- Melanomas of the skin that were incompletely removed
- “Regressed” melanomas: When your body’s immune system may have destroyed a portion of the cancerous cells in a cutaneous melanoma but not before some melanoma cells were able to get into lymph nodes or blood vessels
- Pigmented cells that traveled to the lymph nodes and were transformed into melanoma.
Pediatric Melanoma
Pediatric melanoma is rare. According to the National Cancer Institute, about 400 individuals under 20 years old are diagnosed with melanoma each year. Pediatric melanoma is defined as melanoma occurring in patients younger than 18 years, so we can assume the number of pediatric melanoma cases diagnosed each year is slightly less than 400. As in adults, the most common type of melanoma in children is cutaneous melanoma. Pediatric melanoma that is diagnosed before age 10 is different from melanoma in adults, and melanoma diagnosed after age 10 is very similar to that in adults. Read more about pediatric melanoma here.
Watch this video for more information on melanoma subtypes: