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

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 Ⓡ 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. (Ann Dermatol (Seoul) 20(1) 18∼21, 2008)

Melanoacanthoma: a potential pitfall of reflectance confocal microscopy

“…CM is an uncommon neoplasm histologically characterized by proliferation of epidermal keratinocytes and large dendritic melanocytes. The melanocytes are scattered throughout the tumor 3, 4, 5. The exact incidence of CM among the SK histopathological subtypes is unclear.…”

Melanoacanthoma Masquerading as Melanoma: Case Reports and Literature Review

“…Indeed, using a chromogen with a red indicator may also be helpful in identifying melanoacanthoma by differentiating melanocytes from melanin-laden keratinocytes. Cytokeratin such as CK7, which shows positive staining of the keratinocytes in melanoacanthoma, is a marker that can aid in differentiating melanoacanthoma from melanoma [14].…”