Perpendicular white lines
Nodular melanoma is different to superficial spreading melanoma. It has a nodular component and the dermal component occupies almost as much area as the epidermal component.
The growth rate of nodular melanomas is high compared to more common melanomas and they tend to be more advanced at presentation. Frequently they are amelanotic, and if pigmented may be symmetrical, though this varies.
One common finding with many nodular melanomas is perpendicular white lines, which correlate with vertical bands of collagen