Melanoacanthoma

Melanoacanthoma is a rare, benign skin lesion that is characterized by an increase in both melanocytes and keratinocytes. It was first described in the medical literature by Bloch in 1927. Melanoacanthoma predominantly affects adults and is most commonly found on the head, neck, and trunk. However, it can occur at any age and on any part of the body.

Clinical Presentation

Melanoacanthoma presents as a solitary, well-defined, flat or slightly raised, brown to black patch or plaque. The size can vary from a few millimeters to several centimeters. It is usually asymptomatic, but some patients may report mild itching.

Pathogenesis

The exact cause of melanoacanthoma is unknown. It is believed to result from a reactive proliferation of melanocytes and keratinocytes, possibly in response to an unknown stimulus. Some researchers suggest that it may be related to chronic irritation or trauma, but this has not been definitively proven.

Diagnosis

The diagnosis of melanoacanthoma is primarily based on clinical examination and histopathology. The lesion has a characteristic appearance under the microscope, with an acanthotic epidermis and increased number of melanocytes. The melanocytes are usually located at the base of the epidermis and extend into the stratum corneum, giving the lesion its dark color.

Treatment

As melanoacanthoma is a benign lesion, treatment is not usually necessary. However, if the lesion is causing discomfort or is cosmetically unacceptable, it can be removed by surgical excision, cryotherapy, or laser therapy.

Prognosis

The prognosis for melanoacanthoma is excellent. It is a benign lesion and does not have any malignant potential. However, it can be cosmetically disfiguring and may cause psychological distress to the patient.

See Also

• Melanoma
• Seborrheic keratosis
• Dermatosis Papulosa Nigra