Giant cutaneous melanoacanthoma

Abstract

A 45‐year‐old male cook was seen for the evaluation and removal of a “mole on my eye” of steady growth during the previous 6 months. The patient stated that he had had a “brown spot” above his left eye for 17 years prior to its recent enlargement; it was now partly blocking the vision in his left eye. He denied a history or family history of cutaneous tumors, including skin cancer. On examination, a 2.5‐cm × 0.5‐cm × 0.8‐cm, horn‐like, darkly pigmented, cutaneous nodule was evident extending from the left upper eyelid downwards to below the lower eyelid (Figs 1 and 2). He also had scattered, skin‐colored, 2–3‐mm cystic papules on his anterior mid‐chest. A shave excision specimen was obtained from the eyelid nodule. 1 Horn‐like, cutaneous nodule extending from the left upper eyelid downwards to below the lower eyelid 2 Close up, demonstrating the morphologic features to better advantage Microscopic examination demonstrated acanthosis, hyperkeratosis, and papillomatosis (Fig. 3). Large dendritic cells with abundant melanin granules were spread throughout the epidermis. In addition, small basaloid or spinous keratinocytes were present in the malpighian layer. 3 Histology of the nodule, showing an epidermis with acanthosis, hyperkeratosis, papillomatosis, and large dendritic cells with abundant melanin granules spread throughout the epidermis (hematoxylin and eosin; original magnification, × 100)

Multifocal cutaneous melanoacanthoma with ulceration: A case report with review of literature

“…Occasionally, it can also present as a cutaneous horn. [13] Mostly lesions are sessile but occasionally may be pedunculated, particularly in the major flexures. [7] The lesions vary in size with a diameter ranging from a few millimeters to several centimeters and are most frequently found on the head, particularly the lips, and the trunk.…”

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

“…Dopa or silver stains show melanocytes scattered throughout the entire epidermis and hyperinfiltrations of melanin. Electron microscopic studies reveal large highly dendritic melanocytes with abundant melanin granules in epidermis 5 . Some authors suggest that melanoacanthoma does not deserve a special denomination because the presence of a striking number of dendritic melanocytes at suprabasal levels is a frequent finding in every type of seborrheic keratosis, other than of the reticulated type 6 .…”

“…Recently, Kihiczak et al 5 suggested dendritic melanocytes are large and are situated not only in the suprabasalar area, but throughout all levels of epidermis in the true melanoacanthoma. In addition, unlike pigmented seborrheic keratoses, electron microscopic studies show a partial or complete disruption of melanin transfer from the highly dendritic melanocytes to neighboring keratinocytes, thus there are a few melanin in the cytoplasms of keratinocytes 5,7 . We performed S-100 and melan-A immunohistochemical staining using VECTOR Ⓡ NovaRED TM as a chromogen to distinguish melanocytes clearly from the melanin-laden keratinocytes, because the brown chromogen which is usually used can not provide sufficient contrast for the differentiation of positive immunostaining from the brown cutaneous pigment.…”

“…Some authors suggest that melanoacanthoma does not deserve a special denomination because the presence of a striking number of dendritic melanocytes at suprabasal levels is a frequent finding in every type of seborrheic keratosis, other than of the reticulated type 6 . However like most authors, we consider melanoacanthoma to be a clinically and histologically distinct entity [1][2][3]5 . Recently, Kihiczak et al 5 suggested dendritic melanocytes are large and are situated not only in the suprabasalar area, but throughout all levels of epidermis in the true melanoacanthoma.…”

“…However like most authors, we consider melanoacanthoma to be a clinically and histologically distinct entity [1][2][3]5 . Recently, Kihiczak et al 5 suggested dendritic melanocytes are large and are situated not only in the suprabasalar area, but throughout all levels of epidermis in the true melanoacanthoma. In addition, unlike pigmented seborrheic keratoses, electron microscopic studies show a partial or complete disruption of melanin transfer from the highly dendritic melanocytes to neighboring keratinocytes, thus there are a few melanin in the cytoplasms of keratinocytes 5,7 .…”