Quick recognition and a clear understanding of the most common benign tumors are advantageous for clinicians. Confident reassurance helps to alleviate the concern of a patient but identifying a possible malignant lesion is crucial to further evaluation or referral. Knowledge of benign lesions will allow the clinician to first screen and differentiate those with simple or no required treatment from those that are of true concern.
The first section of this chapter covers benign tumors that are usually seen in adults. The second section of this chapter covers vascular tumors and vascular malformations in infants and children.
Incredibly common, one or more seborrheic keratosis is present in approximately 50% of adults. They are more common in lighter skin types, with some patients having hundreds scattered throughout their skin. Seborrheic keratoses occur on almost any skin surface, except for the palms and soles.1 The pathogenesis is unknown, but they are more common in areas of sun exposure.
Many patients with seborrheic keratoses present with the concern of a changing pigmented "mole" with fear that it may be melanoma or skin cancer. Seborrheic keratoses can arise de novo or start as a macule (used to be flat, but now it's raised). Patients may complain of pain and pruritus if the seborrheic keratosis is irritated by clothing. Seborrheic keratosis appears to be stuck on such that some patients will report scratching off the papule only to have it recur.
A classic seborrheic keratosis has a predilection for the trunk and presents as a well-defined hyperpigmented, ovoid papule, or plaque with a waxy texture and scaly surface. Multiple lesions are more common than a solitary one. Sizes range from a few millimeters to several centimeters in diameter (Figure 20-1). They are often oval with the long axis parallel to relaxed skin tension lines nearby. The astute clinician can quickly recognize these common lesions averting a biopsy, but occasionally the classic features of a seborrheic keratosis are obscured, and a biopsy is prudent. One morphologic variant is a macular seborrheic keratosis, common on the back, face, and scalp which presents as a macule or minimally elevated velvety plaque. The lack of a classic waxy texture allows for misdiagnosis of a solar lentigo or worse, melanoma. A facial variant is dermatosis papulosa nigra (DPN) which presents primarily in African American individuals as small dark papules scattered on the cheeks (Figure 20-2). Stucco keratosis is another variant that presents as multiple small, lightly pigmented, or white keratotic papules on the distal lower extremities resembling the texture of a stucco wall (Figure 20-3).
Seborrheic keratosis. Tan to brown stuck on appearing ...