Solar Lentigines - Age Spots

A 68-year-old fair-skinned woman (Fitzpatrick skin type II) presents with multiple brown spots on the dorsa of both hands, forearms, and cheeks that have appeared gradually over 15 years. She worked as a farmer with cumulative UV exposure and never used sunscreen. On examination, the lesions marked **B** in the diagram are sharply demarcated, uniformly light-to-dark-tan macules, 3–10 mm in diameter, with regular borders, distributed over sun-exposed areas. They do not fade in winter, are flat and non-palpable, and show no asymmetry, irregular borders, or colour variation. Dermoscopy shows a regular fine pigment network and moth-eaten border without atypia. What is the most likely diagnosis?