PMC8009706_01
Halo nevus on the left upper arm. The central part shows only a light shadow while the rest of the lesion is depigmented.
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fig1
A 43-year-old man without medical history presented with an existing irregular halo and depigmented macule on the left upper arm for two and a half years that had changed according to the patient (Figure 1).
Intradermal atypical nevus cells in the left part of the biopsy, contrasting with regression in the right part (HE 5x).
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fig2
Histology of the halo nevus showed intradermal atypical nevus cells but also extensive regression in the superficial dermis (Figures 2 and 3).
Signs of extensive regression in the superficial dermis, lacking atypical melanocytes (HE 20x).
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fig3
Histology of the halo nevus showed intradermal atypical nevus cells but also extensive regression in the superficial dermis (Figures 2 and 3).
PMC8009706_02
Nevus on the right temporal area surrounded by a symmetrical rim of depigmentation.
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fig4
Clinical evaluation revealed a nevus with a halo of depigmentation measuring six by eight millimetres, with a central zone of homogenic pigmentation (Figure 4).
The lesion is characterized by atypical junctional activity and signs of extensive regression in the superficial dermis (HE x 10).
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fig5
Histology showed a melanocytic lesion with extensive regression at the margins of the lesion with only a few atypical cells in the dermis (Figure 5).
Immunohistochemistry shows bridging and pagetoid spread of atypical melanocytes (Melan A red x 10).
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fig6
In contrast, the centre of the lesion showed dense melanocytic proliferation with severe atypical features in the dermoepidermal junction as well as in the dermis (Figures 6).