Evolution of a 4 mm<unk> .<unk>  <unk>  is the most aggressive form of melanoma. It tends to grow more rapidly in thickness (vertically penetrate the skin) than in diameter compared to other melanoma subtypes. Instead of arising from a pre-existing mole, it may appear in a spot where a lesion did not previously exist. Since<unk>  tends to grow in depth more quickly than it does in width, and can occur in a place that did not have a previous lesion, the prognosis is often worse because it takes longer for a person to be aware of the changes.<unk>  is most often darkly pigmented; however, some<unk>  lesions can be light brown, multicolored or even colorless (non-pigmented). A light-colored or non-pigmented<unk>  lesion may escape detection because the appearance is not alarming, however an ulcerated and/or bleeding lesion is common. Polypoid melanoma is a virulent variant of<unk> . The microscopic hallmarks are: * Dome-shaped at low power * Epidermis thin or normal * Dermal nodule of melanocytes with a 'pushing' growth pattern * No "radial growth phase" __NOTOC__
Nodular melanoma
Pseudomelanoma
Lentigo maligna melanoma
Polypoid melanoma
Acral lentiginous melanoma
Amelanotic melanoma
Animal-type melanoma
Superficial spreading melanoma