The most likely diagnosis for a 65-year-old with brown plaques that have a greasy, stuck-on appearance is which?

• A. Lentigines
• B. Actinic keratosis
• C. Keratoacanthomas
• D. Seborrheic keratosis

Answer: (D)

Recognize seborrheic keratosis, a common benign skin lesion in older adults that presents as brown to black, waxy plaques with a greasy, “stuck-on” appearance. This surface and texture come from hyperkeratosis with keratin-filled structures, and the lesions often appear on the trunk, face, or extremities as they age. In a 65-year-old with multiple brown plaques that look greasy and resemble they’re “stuck on,” seborrheic keratosis fits this description best.

Lentigines are flat, uniformly pigmented spots without a raised, greasy surface. Actinic keratosis presents as rough, scaly patches on sun-exposed skin and can be precancerous, not typically described as greasy plaques. Keratoacanthoma is a rapidly growing dome-shaped lesion with a central keratin plug, usually solitary and expanding quickly, not the described stuck-on plaques.