A 78-year-old woman has multiple long-standing lesions on her face and back. These well-circumscribed lesions are tan to brownish, slightly raised with a rough surface, and typically 0.5 to 1.5 cm in diameter. The clinician examining the patient is able to "peel away" pas of the lesion with the dull side of a scalpel blade. Which of the following diagnoses is most likely?

Seborrheic keratoses, as described in the question stem, are very common lesions of the skin of middle-aged and older individuals. These benign growths histologically show hyperplasia of the epidermis. While cosmetically disturbing to some patients, the primary medical concern is that, occasionally, seborrheic keratoses may mimic the clinical appearance of basal cell carcinomas or squamous cell carcinomas. Consequently, biopsy should be performed on atypical appearing or rapidly changing "seborrheic keratoses" to exclude the presence of cancer. Chronic eczema produces dry, thick, and sometimes discolored skin. Melanomas characteristically look like dark moles with irregular margins and variations in the degree of pigmentation. Psoriasis produces erythematous plaques with a silvery scale. Ref: Thomas V.D., Snavely N.R., Lee K.K., Swanson N.A. (2012). Chapter 118. Benign Epithelial Tumors, Hamaomas, and Hyperplasias. In L.A. Goldsmith, S.I. Katz, B.A. Gilchrest, A.S. Paller, D.J. Leffell, N.A. Dallas (Eds), Fitzpatrick's Dermatology in General Medicine, 8e.