How is natural hx of melanoma?

➢ The earliest recognizable phase of melanoma development is proposed to consist of lateral expansion of melanocytes along the dermoepidermal junction (lentiginous hyperplasia and lentiginous compound nevus;) ➢ This then progresses to the phase of melanoma in situ, which is marked by radial growth within the epidermis, often for a prolonged period. ➢ During this stage, melanoma cells do not have the capacity to invade and metastasize. ➢ With time, a vertical growth phase supervenes, in which the tumor grows downward into the deeper dermal layers as an expansile mass lacking cellular maturation ➢ This event often is heralded by the development of a nodule in a previously flat lesion and correlates with the emergence of metastatic