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

We report a case of a 58-year-old female patient who presented with multiple, asymptomatic, slowly-growing, raised pigmented lesions all over her body for the past 10 years with ulceration in one of the lesions on the trunk for the past five months. Histopathology of the lesion revealed features consistent with melanoacanthoma. Here, we report the first case of cutaneous melanoacanthoma presenting with an ulcerated plaque and the third case of cutaneous melanoacanthoma with multiple lesions. To the best of our knowledge, ulceration has not yet been reported as a feature of cutaneous melanoacanthoma in the medical literature.

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

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.

A Case of Melanoacanthoma on the External Auditory Canal / 대한피부과학회지

Melanoacanthoma, a rare benign variant of seborrheic keratosis, was first introduced by Mishima and Pinkus in 1960. It is a slow-growing, painless, pigmented plaque with a verrucous surface and a diameter ranging from a few millimeters to 10 cm. It tends to develop during middle-age with an equal sex incidence, and the lesion usually presents on the head, trunk, and especially the lip. It also has a histopathologic finding of mixed neoplasm composed of melanocytes scattered throughout keratinocytic lobules, and is characterized by hyperkeratosis, parakeratosis, acanthosis, papillomatosis and pseudo-horn cysts in the epidermis. We report a case of melanoacanthoma occurring in a 52-year-old female, who presented with an easily bleeding mass on her right external auditory canal, an extremely uncommon site.

A Case of Melanoacanthoma

Melanoacanthoma is a variant of seborrheic keratosis which was first introduced by Mishima and Pinkus in 1960. This is a very rare and benign, epidermal tumor. Clinically, it is usually manifested in a pigmented, verrucous, round or oval plaque and nodular lesion. This is characterized histologically by nonpigmented keratinocytes and numerous large, richly dendritic melanocytes. We describe a 68-year-old man who suffered from a black-colored plaque on his right shin for 5 years. Melanoacanthoma was diagnosed by characteristic histopathologic findings.