They may occur on any part of the body but have a predilection for the trunk, shoulder, face, and scalp. They begin as small, thin, sharply circumscribed, smooth, light yellow or tan plaques and with time increase in thickness and develop a greasy crust. Examination of a lesion with a hand lens will demonstrate numerous keratin filled follicular openings scattered over the surface. Occasionally traumatized lesions may become inflamed and present some difficulty in the differential diagnosis. Treatment is usually not necessary in those lesions in which the diagnosis is in doubt.
Surgical excision is the treatment of choice.
Cosmetic removal may be achieved by a light curettage electrodesiccation alone or a combination of the two. An excellent cosmetic result may also be obtained with liquid nitrogen or carbon dioxide freezing. This typical seborrheic keratosis is exophytic and has multiple keratin pearls. Another seborrheic keratosis which has been moistened with alcohol to demonstrate the multiple keratin pearls. This is characteristically a polyploid raised, bright red to deep purple lesions involving the dermis and subcutaneous tissue which is present at or appears shortly after birth.