c15t3P1: MDM of dermal type, migrant vertical growth, relative absence of inflammation. It is difficult to diagnose this lesion as melanoma, if the observer is not familiar with the pattern.
c15t3P2: The lesion is a solid nodule showing extension of nests of tumor cells into the reticular dermis among collagen bundles (migrant vertical growth).
c15t3P3: In this example of MDM, the nests of cells are closely spaced in the pattern of typical vertical growth. This lesion did not show significant lentiginous and junctional components; it qualifies as a dermal variant. There is a mitotic figure above the black artefact near the bottom of the field. Degree of atypia is moderate.
c15t3P4: In another field, the lesion is rather solid but cytologically monotonous.
c15t3P5: This is classic MDM of the dermal type. In this example, the cells are pale and epithelioid (rounded with abundant cytoplasm). There is variation in nuclear size and outlines, but nuclear characteristics are rather monotonous and bland. Cells with the same cytologic features may be seen in the vertical growth component of MDM of halo nevus-type (dermal variant).
c15t3P6: This is another field of the same lesion as fig. c10t3P5. The cytologic features are sufficiently distinctive to make a strong case for this being a dermal variant of MDM. Lesions of this type do metastasize, but the metastases may not be manifested until several years after the excision of the primary lesion.
