Nodular melanomas constitute 15 to 30 percent of all melanomas, but cause approximately half of melanoma-related deaths. They typically present as a darkly pigmented, pedunculated or polypoid nodule. They often resemble a mole, bug bite, or pimple. They can occur in any part of the body, but usually appear on areas that receive the most sun exposure such as the head, legs, and arms.
Plotnick H, Rachmaninoff N, Vandenberg HJ. Polypoid melanoma: a virulent variant of nodular melanoma. Report of three cases and literature review. J Am Acad Dermatol. 1990;23(5 Pt 1):880-4.