Malignant Melanoma In Situ in New Lesion With Subtle Gross Features

May 4, 2013
Ted Rosen, MD

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.

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