(4) Tumor. A tumor is an elevated, solid lesion greater than 2 cm. Tumor, a
general term for any mass, benign or malignant, is sometimes used to indicate a large
nodule. The skin is an extremely common site for a wide variety of tumors; most are
easily visible in the earliest stages. Therefore, it is possible to recognize and eradicate
tumors in almost 100 percent of the cases. The following are a few of the origins of skin
tumors: tumors arising from the epidermis surface; tumors arising from epidermal
appendages such as hair structures, sebaceous glands, and sweat glands. Examples
of common skin tumors are actinic keratoses, usually caused by repeated exposure to
sunlight over the years. These tumors are frequently noted in middle-age sailors,
sportsmen, and farmers. Actinic keratoses are more common in the Southwestern US
than in areas with less sunlight. Fair-skinned people are more susceptible to these
tumors than those with dark skin. People who are bald frequently develop multiple
(5) Wheal. A wheal (figure 3-6) is an elevated lesion (rounded or flat-
topped). A wheal has increased tissue fluid, often itches, and usually disappears within
a few hours. Trace the wheal with a skin marking pencil, observing over a period of
time. You will see the lesions shift rapidly from involved to uninvolved adjacent skin
areas. The lesions are the result of excess fluid in the upper layer of the dermis.
Wheals are pale red and may be an allergic response to any one of a number of irritants
or to insect bites. Twenty-five percent of the normal population can produce wheals
merely by stroking their skin. This phenomenon is called dermatographism. The size of
wheals varies from 3 to 4 mm in diameter as in the skin disease cholinergic urticaria or
10 to 12 mm as in the skin diseases composed of erythematous plaques.
Figure 3-6. Wheal.
(6) Plaque. A plaque (figure 3-7) is a rather large surface area which is
elevated above the surrounding skin surface. In the skin disease psoriasis, a number of
papules form the plaque. In the skin disease lichenification, the skin on the plaque
appears thickened, and the skin markings are more visible than usual. Also, the surface
of the skin lesions may resemble tree bark. Lichenification is caused by repeatedly
rubbing a skin area.