The radial growth phase may last for years and never develop a vertical growth phase. The risk of progression of LM to LMM varies with age, but is lower than commonly believed. These risk estimates apply to patients in whom LM is discovered incidentally. LMM may have a complex patten. The color is more uniform than SSM, but red and white may later occur.
Tumors are generally in the center of the lesion, away from the border.
LMM may ulcerate or undergo changes similar to other lesions when they enter the tumor stage. Nodules are usually single and generally appear when the lesion has assumed a size of 5 to 7 cm, but may occur in much smaller lesions. Acral-lentiginous melenoma . ALM appears on the palms, soles, terminal phalanges, and mucous membranes. Similar in clinical presentation to LM and LMM, ALM has the same colors and tendency to remain flat.