Case Study : Dermatology
108. Benign Blue Nevus
108. Dark mole on face
A 19-year-old woman presented to her family physician (FP) with a dark mole on her face.
She said that the mole had been there for more than 5 years, but indicated that it had been getting darker.
She was worried that it might be skin cancer and wanted it removed.
The physician noted a 4-mm darkly pigmented, slightly raised lesion.
The patient denied any personal or family history of skin cancer.
Benign Blue Nevus
The physician suspected that this was a benign blue nevus because it had a regular border and was uniformly dark in color. He also recognized that melanoma is very rare at age 19. That said, it is hard to ignore a changing mole that is so black in color.
The patient wanted it removed, so a 5-mm punch biopsy was performed.
When the punch core was removed, the physician noted that the pigment was visible in the deep dermis (as expected with a blue nevus).
A single suture was placed, and the patient was scheduled for follow-up in one week. The pathology report came back as a blue nevus, which is completely benign.
While many blue nevi actually appear blue because of the Tyndall effect causing the dark melanin in the deep dermis to create a blue coloration, some will appear black (as was seen in this case).
On the follow-up visit, the suture was removed and the incision was healing well. The patient was reassured that this was a benign mole and was happy with the cosmetic result.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD.
This case was adapted from: Smith M, Usatine R. Benign nevi. In: Usatine R, Smith M, Mayeaux EJ, et al.
Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill; 2013:945-952
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