An irregular pigmented lesion on the back

An 87-year-old woman with a history of multiple basal cell carcinomas presented to a follow-up visit referring a pigmented, slowly growing lesion on her right scapula that had been present for one year. Physical examination revealed an irregular 12 x 5 mm well circumscribed pigmented lesion with an elevated keratotic surface (Figure 1). The dermoscopic evaluation revealed a multicomponent pattern: many colors, superior irregular pigmented network with blue-white veil and inferior cerebriform pattern surrounded by atypical pigmented network with sharp demarcation (Figure 2). The patient underwent complete exeresis of the lesion and the specimen was stained with hematoxylin-eosin. Histopathological examination showed a papillomatous epidermal hyperplasia with hyperkeratosis and cell nests in the dermoepidermal junction (Figure 3) and proliferation of atypical intraepidermal melanocytes with a pagetoid spread (Figure 4). What is your diagnosis? An irregular pigmented lesion on the back