Which of the following is a benign, flat pigmented spot on the skin?

• A. Lentigo
• B. Basal cell carcinoma
• C. Melanoma
• D. Squamous cell carcinoma

Answer: (A)

A benign flat pigmented patch is most consistent with lentigo. Lentigines are flat macules caused by an increased number of melanocytes in the basal layer, often on sun-exposed skin. They have a uniform brown or tan color with well-defined borders and tend to stay flat and stable over time. This stability and uniformity set them apart from malignant lesions.

Basal cell carcinoma and squamous cell carcinoma can sometimes be pigmented, but they usually present as raised, scaly, crusted, or ulcerated lesions rather than flat patches of uniform color. Melanoma typically shows asymmetry, irregular borders, multiple colors, and evolution in size or shape; it is not a flat, uniform patch.