Nodular melanomas (NM) share many histologic features with superficial spreading melanoma. However, NM are sharply circumscribed and show a vertical (invasive) growth pattern (as seen here). They are not preceded by a radial growth phase. The intraepidermal atypical melanocytes are not seen beyond three epidermal ridges on either side of the tumor nodule - i.e. the epidermal component does not extend laterally in relationship to the dermal component creating a well-defined nodule.