any of several malignant neoplasms (usually of the skin) consisting of melanocytes
"After noticing a strange spot on his arm, the doctor confirmed that it was an early stage of melanoma affecting the pigment cells in his skin."
A dark-pigmented, usually malignant tumor arising from a melanocyte and occurring most commonly in the skin.
"After noticing a new mole that was changing color and shape, I rushed to the doctor for a biopsy to rule out melanoma."