Older adult presents with concern about a specific asymptomatic lesion on his chest of unknown duration. History includes extensive solar exposure without sunscreen use.
Key point: The shape is somewhat irregular with a prominent notch to the left side; there is irregularity of pigment as well. These signs suggest a high probability of malignancy, with pigmented basal cell carcinoma and malignant melanoma being most likely.
Treatment: Either an incisional or excisional biopsy is mandatory. Because of the relatively small size, complete removal is probably preferable in this case.
Note: The lesion ended up being a superficial spreading malignant melanoma, 0.37-mm thick, with only rare mitoses visualized on histology. Following excision, this thin, stage IA lesion carries a good prognosis (97% 5-year survival).