Seborrheic keratosis
Benign
Not related to sun exposure (can be anywhere)
Proliferation (hyperplasia) of small stratum basale cells that have melanin inside (epidermis)
Hyperkeratosis on top of lesions
Small keratin-filled cysts (horn cysts) on top of lesions (superficial)
Downgrowth of keratin into the main tumor mass (pseudo-horn cysts) (in dermis)
middle-age and older











