PMC3663382_01
(A) A dark brown-to-black hyperkeratotic plaque measuring 10 mm in diameter on the left sole. The border was well circumscribed and symmetrical. (B) A clinical examination after biopsy revealed several pigmented macules of different shades varying from brown to black around the central hyperkeratotic lesion. [Copyright:  2013 Ise et al.]
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An 81-year-old Japanese woman presented with a pigmented skin lesion on the left heel (Figure 1). A detailed inspection of the remaining lesion revealed surrounding pigmented macules with different shades of brown-to-black and diffuse irregular hypopigmentation (Figure 1B).
Dermoscopic examinations of: (A) A hyperkeratotic lesion:scaly surface and regular brown-to-black dots/globules. (B) Surrounding macules:many brown-to-black macules. Most of them showed parallel ridge pattern. [Copyright:  2013 Ise et al.]
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Dermoscopic examination demonstrated a scaly surface and regular brown-to-black dots/globules (Figure 2). The pigmented macules showed the parallel ridge pattern on dermoscopy (Figure 2B).
(A) Hematoxylin and eosin staining revealed remarkable hyperkeratosis and many large nests of atypical melanocytes at the dermoepidermal junction. (B) Nests of atypical melanocytes ascending into the stratum corneum. (C) The nests are composed of atypical cells, and mitoses were also observed. Eosinophilic structures resembling Kamino bodies were also seen. [Copyright:  2013 Ise et al.]
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Conventional histopathologic staining with hematoxylin and eosin of the central lesion revealed marked hyperkeratosis and proliferating nests composed of atypical melanocytes within the epidermis (Figure 3A). Nests ascending into the stratum corneum were also seen (Figure 3B). Atypical melanocytes forming nests demonstrated substantial nuclear atypia and mitoses (Figure 3C).