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MDMHALO

MDMLMM

NEVOIDMDM

MDMhalo, metastasizing

Near-neoplasia

General Index

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PICTORIAL 1

PICTORIAL 2

PICTORIAL 3

PICTORIAL 4

P3-1: The boundary between junctional components and the dermal fascicles of epithelioid cells is defined by a green line. Generally, there is no continuity between the two in this area; it does not appear that the epidermal component has made a significant contribution to the dermal component. The cells of the dermal fascicles are mostly rounded in outline and have enlarged nuclei with open chromatin patterns and small, central nucleoli; some are plump, short spindle cells. The cytologic features of the dermal population of epithelioid cells are remarkably uniform. The patterns in the area showing a preponderance of epithelioid cells are representative of near-neoplasia of halo nevus-like type, dermal variant: the progressions in the dermal component appear to be independent of the junctional component.

P3-2: The area showing prominent halo nevus-like phenomena also is composed of epithelioid cells in fascicular patterns. The epithelioid cells of the fascicles seem to be more uniformly spindle shaped in this site. The fascicles are thin and tortuous. They are associated with dense, uniform infiltrates of lymphoid cells. A few scattered, dermal nests of pigmented, small nevus cells are also represented in the lymphoid infiltrates. Even in this area, continuity between junctional nests and dermal nests of nevus-like cells is difficult to demonstrate.

P3-3: In some areas, the infiltrates are more sheet-like; fascicles are less defined. Spotty lytic defects contain loose infiltrates of lymphocyte.  The epithelioid cells are round; their cytologic features are remarkably uniform.

P3-4: The junctional component, the small, nevus-cell component (green arrows), and the epithelioid component (blue-green arrows) are all represented. Cytolytic defects (red arrows) are also represented. The cells of the junctional components are cytologically different from those of the dermal epithelioid cell component. The lytic defects are prototypic of halo nevus-like phenomena (conceptually, they are the equivalent of a lichenoid reaction in which the target cells are of melanocytic lineage..

P3-5: As in P3-4, the pigmented, small cell component (green arrows), the epithelioid component, and lymphocyte-mediated, cytolytic phenomena (blue-green arrows) are represented. In addition, a sequential change related to the halo nevus-like phenomena is represented; a zone of laminated fibrous tissue is interpreted as a late sequential change related to the halo nevus-like phenomena (red arrows).