Elastic fiber pattern in regressing melanoma: a histochemical and immunohistochemical study.
BACKGROUND
Although histopathologic identification of regression of melanoma is usually straightforward, sometimes it can be difficult to distinguish it from scarring fibrosis. Therefore, this study investigates the elastic fiber pattern in melanomas associated with either regression or scars.


METHODS
We compared 33 invasive melanomas with the fibrosing stage of regression to 10 cases of invasive melanomas with scarring fibrosis. None of the regression cases had a prior surgical procedure. Elastic fiber patterns were evaluated with Verhoeff's elastic van Gieson stain (EVG) and elastin immunostain.


RESULTS
Elastin immunostain was superior to EVG in revealing the elastic fiber patterns. Both regression and scars had decreased to absent elastic fibers in the areas of fibrosis. However, areas of regression had a well-defined compressed layer of thin elastic fibers pushed down from the papillary dermis to the base of the fibrosis. In contrast, the base of scars lacked this compressed elastic layer and had instead an abrupt transition to the thick elastic fibers of the spared reticular dermis.


CONCLUSIONS
We have identified distinct changes of the elastic tissue network, which more accurately define the presence of regression in melanoma and distinguish it from scarring fibrosis.
Kamino
Hideko
H
Department of Dermatology, New York University Langone Medical Center, New York, NY, USA. HIDEKO.KAMINO@nyumc.org
Tam
Sam
S
Roses
Daniel
D
Toussaint
Sonia
S
D002921:Cicatrix / Q000473:pathology; D004547:Elastic Tissue / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000473:pathology*; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*