Acral lentiginous melanoma is a relatively serious form of melanoma because it's usually not caught till it's pretty well advanced. When detected early, the cancerous growth may be successfully removed through surgery. However, acral lentiginous melanoma usually isn't diagnosed till later, because the growths often occur in "hidden" places and may look like a simple bruise or nail infection, so many people don't think it's problematic. Sometimes, growths may not be pigmented, which also leads people to believe that they're not serious problems. The combination of a lack of early diagnosis and the fact that the disease progresses quickly makes acral lentiginous melanoma relatively serious. See your doctor right away if you notice any suspicious symptoms.