Verhoeff-van Gieson May Distinguish Desmoplastic Melanoma From Re-Excision Scar

Area of Science:

• Dermatopathology
• Histology
• Oncology

Background:

• Desmoplastic melanoma (DM) diagnosis is challenging due to its resemblance to scar tissue.
• Standard immunohistochemical stains like S100 and SOX10 can be positive in both DM and scar tissue, complicating differentiation.
• Distinguishing residual DM from scar tissue in re-excision specimens is critical, especially for regressed or traumatized lesions.

Purpose of the Study:

• To evaluate the utility of the Verhoeff-van Gieson (EVG) stain in differentiating desmoplastic melanoma (DM) from scar tissue.
• To compare the distribution of elastin fibers in DM specimens versus re-excision scar specimens.

Main Methods:

• Seventeen DM specimens and seventeen re-excision scar specimens were stained using the Verhoeff-van Gieson (EVG) stain.
• The distribution and presence of elastin fibers were analyzed in both DM and scar tissues.

Main Results:

• 76% (13/17) of DM specimens showed preserved elastic fibers between melanocytes.
• 100% of scar specimens lacked elastin.
• Some DM cases showed elastin at the base or were devoid of elastin, potentially due to age or delayed excision.

Conclusions:

• The EVG stain may be a useful tool for differentiating DM from scar tissue when elastin is preserved between melanocytes.
• Caution is advised in interpreting EVG results when intratumoral elastin is absent, particularly in elderly patients or after significant delays in excision.