Melanoma : Vertical Growth Phase
Vertical growth phase of melanomas consists of cohesive nests, clusters, and nodules of tumor cells invading the dermis. The nests are larger and morphologically different than those in the intraepidermal component with greater pleomorphism, apoptosis and frequent mitoses. Features of regression are usually absent from the tumor base. Vertical growth phase is associated with greater potential for lymphovascular invasion, metastatic spread and adverse prognosis.