Figure 2
From: Prognosticators of melanoma, the melanoma report, and the sentinel lymph node
Vertical growth phase melanoma: The vertical growth phase signifies the point at which the melanoma becomes biologically capable of producing metastatic events. Note that there is a dominant expansile dermal nest of neoplastic melanocytes (arrow) which is larger than any of the overlying theques at the dermal–epidermal junction or within the epidermis. Furthermore, the cytology is typically distinctive in the dominant nest. Mitoses are often present. In the fully evolved vertical growth phase these dominant nodules are noted at level III or IV, while the incipient vertical growth phase tumor would be confined to the papillary dermis (ie Clark level II).
