Ann Dermatol.  2008 Mar;20(1):18-21. 10.5021/ad.2008.20.1.18.

A Case of Melanoacanthoma: Immunohistochemical Staining Using VECTOR(R) NovaRED(TM) to Distinguish Melanocytes from the Cutaneous Pigment

• Choi JE
• Bae EJ
• Kim AR
• Son SW
• Song HJ
• Oh CH

• KMID: 2156354
• DOI: http://doi.org/10.5021/ad.2008.20.1.18

Abstract

Melanoacanthoma is a rare benign mixed tumor of both keratinocytes and melanocytes. Although some authors said that it is a rare variant of seborrheic keratosis, it has clinical and histological features distinct from seborrheic keratosis. It has large dendritic melanin-laden melanocytes throughout all levels of epidermis showing a disruption of melanin transfer from the melanocytes to neighboring keratinocytes. However, it is difficult to distinguish melanocytes clearly from cutaneous pigment in immunohistochemical stain with usually used brown chromogen. We used chromogen with brick-red indicator product (VECTOR(R) NovaRED(TM)) in S-100 and melan-A immunohistochemical staining to distinguish melanocytes from melanin laden keratinocytes. We suggest that the immunohistochemical staining using this novel chromogen may be useful in the diagnosis of melanoacanthoma.

Keyword

Immunohistochemistry; Melanoacanthoma; Seborrheic keratosis; VECTOR(R) NovaRED(TM)

MeSH Terms

Epidermis
Immunohistochemistry
Keratinocytes
Keratosis, Seborrheic
MART-1 Antigen
Melanins
Melanocytes
MART-1 Antigen
Melanins

Figure

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  Fig. 1 About 2 × 2 cm-sized, well-demarcated, black-pigmented plaque on the abdomen.

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  Fig. 2 The epidermis showed hyperkeratosis, acanthosis, papillomatosis and pseudo-horn cysts and the tumor was composed of basaloid and squamous keratinocytes and melanocytes (H&E, × 100).

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  Fig. 3 The tumor consisted of a proliferation of keratinocytes with a low pigment content and numerous heavily stained large dendritic melanocytes spread throughout all levels of the stratum malpighii, which are stained red by chromogen VECTOR® NovaRED™ (A: S-100, × 100; B: melan-A, × 100).

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