Using dermoscopic criteria and patient-related factors for the management of pigmented melanocytic nevi

Abstract

Objective: To review recent dermoscopy studies that provide new insights into the evolution of nevi and their patterns of pigmentation as they contribute to the diagnosis of nevi and the management of pigmented melanocytic nevi.

Data sources: Data for this article were identified by searching the English and German literature by Medline and Journals@Ovid search for the period 1950 to January 2009.

Study selection: The following relevant terms were used: dermoscopy, dermatoscopy, epiluminescence microscopy (ELM), surface microscopy, digital dermoscopy, digital dermatoscopy, digital epiluminescence microscopy, digital surface microscopy, melanocytic skin lesion, nevi, and pigmented skin lesions. There were no exclusion criteria.

Data synthesis: The dermoscopic diagnosis of nevi relies on the following 4 criteria (each of which is characterized by 4 variables): (1) color (black, brown, gray, and blue); (2) pattern (globular, reticular, starburst, and homogeneous blue pattern); (3) pigment distribution (multifocal, central, eccentric, and uniform); and (4) special sites (face, acral areas, nail, and mucosa). In addition, the following 6 factors related to the patient might influence the pattern of pigmentation of the individual nevi: age, skin type, history of melanoma, UV exposure, pregnancy, and growth dynamics.

Conclusions: The 4 x 4 x 6 "rule" may help clinicians remember the basic dermoscopic criteria of nevi and the patient-related factors influencing their patterns. Dermoscopy is a useful technique for diagnosing melanocytic nevi, but the clinician should take additional factors into consideration to optimize the management of cases of pigmented lesions.

Figure 1

Colors allow the physician, to some extent, to draw conclusions about the localization of pigmented cells within the skin. Black and brown (due to melanocytes or pigmented parakeratosis) indicate pigmentation in the epidermis, while gray and blue (due to melanocytes or pigment-laden melanophages) correspond to pigmented cells within the superficial and deep dermis, respectively (hematoxylin-eosin, original magnification ×100).

Figure 2

The 4 main dermoscopic morphologic structures of nevi correspond to specific underlying histopathologic correlates. This allows the physician to draw conclusions about the histopathologic type of nevi. All dermoscopic images are original magnification ×10; all histopathologic images are hematoxylin-eosin stained, original magnification ×100.

Figure 3

Body site–related nevus patterns. Facial, acral, subungual, and mucosal nevi show, respectively, a pseudonetwork pattern, parallel furrow pattern, parallel bandlike pattern, and mixed blue-gray globular homogeneous pattern. All dermoscopic images are original magnification ×20.

Figure 4

Change in nevus pattern and patient age. In prepubertal children and adults older than 60 years, nevi typically reveal a globular pattern, while adolescents exhibit a peripheral rim of globules, and adults show a reticular pattern. All dermoscopic images are original magnification ×10.

Figure 5

Skin type–related prevalent patterns of melanocytic nevi. All dermoscopic images are original magnification ×10.

Figure 6

Complex (A) vs uniform (B) nevus patterns. A, Complex nevus patterns are dermoscopically characterized by the presence of more than 1 morphologic structure (in this example, globules, a network, and homogeneous brown pigmentation). B, Uniform brown reticular nevus showing superficial black dots. Both dermoscopic images are original magnification ×10.

Figure 7

Decision tree for the management of nevi respective dermoscopic patterns and individuals factors influencing the dermoscopic features.

Figure 8

Side-by-side comparison of a nevus (A) and a melanoma arising in a small congenital melanocytic nevus (B), both showing an eccentric focus of hyperpigmentation. A, The nevus shows an overall regular network without additional morphologic structures. B, In contrast, the nevus-associated melanoma reveals additional melanoma-specific patterns such as irregular dots, globules, streaks, and blotches in the latter. Both dermoscopic images are original magnification ×10.

Figure 9

The usefulness of dermoscopy for patients with multiple nevi. A, While the clinical overview of the back of a 53-year-old woman with multiple nevi reveals no obvious suspicious lesions, dermoscopy enables the recognition of a prevalent nevus pattern (B and C), which in consequence allows the immediate identification of a lesion that differs from the other nevi (D). Subsequent excision and histopathologic examination of the lesion located on her lower back (A, square-enclosed area) revealed a clinically inconspicuous melanoma in situ (A, inset) that presented dermoscopically as an ugly duckling lesion. All dermoscopic images are original magnification ×10.

Figure 10

Clinical (insets) and dermoscopic images of evolving lesions. A, Nevus on the chest of a 21-year-old woman might be expected to show a peripheral brown rim of globules. B, However, the same features of an evolving lesion observed on the back of a 61-year-old man are unexpected and should raise the index of suspicion; this lesion was therefore excised and histopathologically diagnosed as melanoma in situ. Both dermoscopic images are original magnification ×10.

Figure 11

Clinical (insets) and dermoscopic images of a Spitz nevus (A) and a spitzoid-appearing melanoma in situ of the superficial spreading type (B). Side-by-side comparison underscores the rule to excise all lesions with spitzoid patterns because no single clinical or dermoscopic criterion allows an accurate differentiation between the nevus and the melanoma. Both dermoscopic images are original magnification ×10.

Figure 12

The diagnosis of blue nevus should be always based on the combination of homogeneous blue color and a long-standing, unchanged history of the lesion. In contrast, blue lesions with a history of changes should be always excised. All dermoscopic images are original magnification ×10.