Nodular melanoma: Nodular melanoma is the most rapidly growing and aggressive variant of malignant melanoma, accounting for about 15% of malignant melanoma cases. It is characterized by a vertical growth phase and the absence of a radial growth phase. Typically, it arises on apparently normal skin, has relatively little melanin and a rich blood supply. Ulceration is common.

Nevus: Small, dark, sometimes raised growth on human skin. Also called a mole.

Nodule: an elevated lesion which is located deep in the cutis. The skin over it can be easily and visibly removed.

Nummular eczema: Coin-shaped patches of irritated skin-most common on the arms, back, buttocks, and lower legs-that may be crusted, scaling, and extremely itchy