Busam KJ, Charles C, Lee G, Halpern AC: Morphologic features of melanocytes, pigmented keratinocytes, and melanophages
by in vivo confocal scanning laser microscopy.
Dermal melasma is characterized by the occurrence of melanophages
(cells that ingest melanin) throughout the dermis.
Rare individual or patchy, pigmented melanocytes and melanophages
were seen in 26 specimens (53%), most of which were superficially located.
These pigmented cells include melanophages
and cells that show squamous differentiation (figure, A).
Some of the benign nevi showed dermal fibroplasia without the associated changes in melanophages
, chronic inflammation, or vascular ectasia that characterize regression.
Histologically, regression can be recognized by the presence of dermal fibrosis, vascular proliferation, inflammatory infiltrate, and presence of melanophages
in association with complete or partial destruction of tumor cells.
34-36) For example, the biopsy specimen in the right postauricular region of an 11-yearold girl consisted of a black-brown nodule (Figure 1, A) that showed histologic features compatible with PEM: heavily pigmented, wedge-shaped tumor (Figure 1, B) composed of long spindle cells with fine dendritic processes and large epithelioid cells, some lightly melanized and others heavily melanized, with round to oval nuclei and numerous darkly pigmented melanophages
(Figure 1, C and D).