Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Pattern analysis: Dermoscopic criteria for specific diagnoses


Dermoscopic analysis of pigmented skin lesions is based on four algorithms:

  • pattern analysis;

  • the ABCD rule;

  • Menzies’ 11-point checklist; and

  • the 7-point checklist.

The common denominator of all these diagnostic algorithms is the identification and analysis of dermoscopic criteria found in the lesions. The majority of the dermatologists who participated in the second consensus meeting were proponents of pattern analysis. The basic principle is that pigmented skin lesions are characterized by global patterns and combinations of local criteria.

Four global dermoscopic patterns for melanocytic nevi

Reticular pattern

The reticular pattern is the most common global pattern in melanocytic lesions. It is characterized by a pigment network covering most parts of a lesion. The pigment network appears as a grid of line segments (honeycomb-like) in different shades of black, brown, or gray. Modifications of the pigment network vary with changes in the biologic behavior of melanocytic skin lesions, and these variations therefore merit special attention.

Globular pattern

Variously sized, round to oval brown structures fill these melanocytic lesions. This pattern can be found in congenital and acquired melanocytic and Clark (dysplastic) nevi.

Homogeneous pattern

This pattern is characterized by a diffuse, uniform, structureless color filling most of the lesion. Colors include black, brown, gray, blue, white, or red. A predominantly bluish color is the morphologic hallmark of blue nevi.

Starburst pattern

The starburst pattern is characterized by the presence of pigmented streaks and/or dots and globules in a radial arrangement at the periphery of a melanocytic lesion. This pattern is the stereotypical morphology in Spitz nevi.

Fig. 61, Nevus.

Fig. 62, Nevus.

Fig. 63, Nevus.

Fig. 64, Nevus.

Fig. 65, Nevus.

Fig. 66, Nevus.

Fig. 67, Nevus.

Fig. 68, Nevus.

Fig. 69, Nevus.

Fig. 70, Nevus.

Fig. 71, Nevus.

Fig. 72, Nevus.

Fig. 73, Nevus.

Fig. 74, Nevus.

Fig. 75, Nevus.

Fig. 76, Nevus.

Fig. 77, Nevus.

Fig. 78, Nevus.

Fig. 79, Nevus.

Fig. 80, Nevus.

Fig. 81, Nevus.

Fig. 82, Nevus.

Fig. 83, Nevus.

Fig. 84, Nevus.

Fig. 85, Nevus.

Fig. 86, Nevus.

Fig. 87, Nevus.

Fig. 88, Nevus.

Fig. 89, Nevus.

Fig. 90, Nevus.

Fig. 91, Nevus.

Fig. 92, Nevus.

Fig. 93, Nevus.

Fig. 94, Nevus.

Fig. 95, Nevus.

Fig. 96, Nevus.

Fig. 97, Nevus.

Fig. 98, Nevus.

Fig. 99, Nevus.

Fig. 100, Nevus.

Fig. 101, Nevus.

Fig. 102, Nevus.

Fig. 103, Nevus.

Fig. 104, Nevus.

Fig. 105, Nevus.

Fig. 106, Nevus.

Fig. 107, Nevus.

Fig. 108, Nevus.

Fig. 109, Nevus.

Fig. 110, Nevus.

Fig. 111, Nevus.

Fig. 112, Nevus.

Fig. 113, Nevus.

Fig. 114, Nevus.

Fig. 115, Nevus.

Fig. 116, Nevus.

Fig. 117, Nevus.

Fig. 118, Nevus.

Fig. 119, Nevus.

Fig. 120, Nevus.

Fig. 121, Nevus.

Fig. 122, Nevus.

Fig. 123, Nevus.

Fig. 124, Nevus.

Fig. 125, Nevus.

Fig. 126, Nevus.

Fig. 127, Nevus.

Fig. 128, Nevus.

Fig. 129, Nevus.

Fig. 130, Nevus.

Fig. 131, Nevus.

Fig. 132, Nevus.

Fig. 133, Nevus.

Fig. 134, Nevus.

Fig. 135, Nevus.

Fig. 136, Nevus.

Fig. 137, Nevus.

Fig. 138, Nevus.

Fig. 139, Nevus.

Fig. 140, Nevus.

Fig. 141, Nevus.

Fig. 142, Nevus.

Fig. 143, Nevus.

Fig. 144, Nevus.

Fig. 145, Nevus.

Fig. 146, Nevus.

Fig. 147, Nevus.

Fig. 148, Nevus.

Diagnosis of melanoma using five melanoma-specific criteria

Melanoma is most often characterized by a multicomponent global appearance. The multicomponent pattern is defined as the presence of three or more distinct dermoscopic areas within a given lesion. For example, it might be made up of separate zones of pigment network, clusters of dots and globules, and areas of diffuse hyper- or hypopigmentation. Many combinations of criteria can be seen with this high-risk global pattern. It is highly suggestive of melanoma but can also be found in basal cell carcinoma. Rarely, it is seen in acquired and congenital nevi and in non-melanocytic lesions, such as seborrheic keratoses or angiokeratomas.

To diagnose melanoma, look for the melanoma-specific criteria in a lesion. Melanoma-specific criteria can be seen in benign and malignant lesions but are more specific for melanomas. Finding one or two is enough to warrant a histopathologic diagnosis.

Atypical pigment network

A low-risk pigment network can appear as a delicate thin grid or a honeycomb-like pattern of brownish lines over a diffuse light-brown background. Histopathologically, the lines of the pigment network represent elongated and hyperpigmented rete ridges, whereas the lighter areas between the lines are dermal papillae. This criterion represents the dermoscopic hallmark of melanocytic lesions. Alterations are helpful to differentiate between benign and malignant melanocytic proliferations.

An atypical pigment network is characterized by black, brown, or gray, thickened and branched line segments, distributed irregularly throughout the lesion. A sharp cutoff of an atypical pigment network at the periphery of a lesion is even more suggestive of melanoma.

Irregular streaks

Streaks are dark linear structures of variable thickness found at the periphery of a lesion. The term “streaks” includes radial streaming and pseudopods, which are variations of the same criterion. Streaks represent discrete, linear, heavily pigmented, junctional nests of atypical melanocytes. Although streaks can be found in benign and malignant melanocytic lesions, they are more specific for melanoma, especially when they are unevenly distributed in a lesion. A symmetrical arrangement of streaks around an entire lesion is most often found in Spitz nevi, but this pattern can also be seen in melanomas.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts