NAVIGATIONAL GUIDE BELOW

EXTERNAL LINKS BELOW

MDMHALO

MDMLMM

NEVOIDMDM

MDMhalo, metastasizing

Near-neoplasia

General Index

LINKS TO PICTORIALS BELOW

PICTORIAL 1

PICTORIAL 2

PICTORIAL 3

PICTORIAL 4

P1-1a: The lesion is polypoid at the surface of the skin. Above the blue arrows, lymphoid infiltrates are band-like. Above the lymphoid infiltrates, the dermal component of the lesion is loosely fasciculated. To the right of this area, there is less inflammation and the lesion appears to be more uniformly cellular (plaque-like or somewhat nodular). There are melanin deposits near the dermal-epidermal interface. The lesion is relatively confined to a widened papillary dermis.

P1-1b: The area to the left in P1-1a is shown at higher magnification. The red arrows are over areas showing junctional components at the dermal-epidermal interface. The blue arrows outline a zone showing halo nevus-like phenomena (i.e., band-like lymphoid infiltrates). The green arrows outline the margin of a zone in which “nevus-like” cells have uniformly acquired epithelioid qualities. The epithelioid “nevus-like” cells in the area above the blue arrows form loosely spaced fascicles (organoid or nevoid patterns: variant vertical growth-like patterns) that extend into the lymphoid infiltrates.

P1-2a: The patterns are basically similar to those in P1-1. The dark columns, that are loosely spaced to the right side of the lesion and perpendicular to the skin surface, are fascicles of pigmented, small nevus cells of a more ordinary type. The lymphoid infiltrates of “halo nevus-like” type are represented to the far left of the field. Vessels at the interface between the lower margin of the lesion and the reticular dermis are dilated. The specialized stroma supporting the vessels separates the nevus-like lesion from the reticular dermis. Extension of the nevus-like lesion into the reticular dermis, a common feature of Spitz nevus, is not a feature of this lesion.

P1-2b: This area area is representative of  the far right of the field illustrated in P1-2a. Fascicles of pigmented nevus cells are identified by blue arrows. Fascicles of epithelioid “nevus-like” cells are fairly closely spaced in the widened papillary dermis among the widely scattered nests of more ordinary, ”common,”,” pigmented nevus cells. There are prominent deposits of melanin near the dermal-epidermal interface. Junctional nests are also a prominent feature. In the vascularized fibrous tissue that has condensed at the interface between the stroma of the lesion and the reticular dermis, there are scattered lymphoid infiltrates. The halo nevus phenomena are not as prominent in this field as in the area to the left that is associated with band-like infiltrates of lymphoid cells in P1-2a.

NOTE 1 (DISCUSSION A): Spindle cells (often pigmented) are a common feature of the junctional components of halo nevus and related variants. Atypical nevus-like cells are also a common feature of the dermal component and in some examples seem to be sequentially related to cells of a junctional component but in other examples seem to be representative of a transformation of dermal “nevus” cells.   Return to Discussion A.