This may have contributed to the higher proliferative activity of nevus cells
during the first stages, whereas with an intradermal nevus the cells become fully matured.
Unlike the assays discussed above that require macro/ microdissection of tumoral melanocytes, which are left vulnerable to inclusion of nuclei from benign precursor nevus cells
, epidermal keratinocytes, or stromal/connective tissue cells, this immunohistochemistry-based assay for 5-hydroxmethylcytosine enables evaluation at a molecular level of each individual cell of interest within the context of an entire histologic section (Figure 2, A through C).
B, Higher magnification of areas with eosinophils that typically infiltrate the epithelium and nevus cells
(hematoxylin-eosin stain, original magnification X40).
Tyrosinase activity in dermal nevus cells
. Arch Dermatol.
(3,5,17) "Dropping off" of junctional nevus cells
into the dermal scar has also been deduced in 36% to 42% of RN, as evidenced by rounded nesting patterns without differentiation into type B or type C nevus cells
(23) Since melanomas commonly arise from nevi, our study suggests that a subpopulation of melanocytes or nevus cells
may bypass the senescent response induced by persistent activation of BRAF, allow accumulation of second or subsequent genetic hits, and gain uncontrolled proliferation capacity.
Thus, when examining an SLN, it may be very important to study the original melanoma and to compare the morphologic features, particularly to distinguish metastatic cells from macrophages or nevus cells
(see also below the section on differential diagnosis).