Malignant Melanoma In Situ in New Lesion With Subtle Gross Features

Eccentric darker pigmentation in this small asymptomatic lesion strongly suggests malignant melanoma. This patient had a history of non-melanoma skin cancer, but was unaware of the questionable growth.

A 47-year-old woman with a history of non-melanoma skin cancer presented for a total body skin check. She had missed several previous appointments and had not been seen in 2 years.

Key point: During the examination, a 5 × 3-mm pigmented macule was noted on the anteromedial aspect of the right foreleg. Most important, the asymptomatic lesion had a small spot of eccentric darker pigmentation. The patient was unaware of the questionable growth.

Treatment: This type of eccentric pigmentation strongly suggests malignant melanoma. Since the lesion was so small, it was excised with 5-mm margins. Histology demonstrated malignant melanoma in situ. No further treatment was required, although the patient was admonished to keep future appointments.

Note: Patients may not notice even the most obviously suspicious skin lesions. Periodic examinations by a qualified health care professional are essential in high-risk individuals.