Definition and score calculation of the 7 dermoscopic criteria

In the original paper on the 7-point checklist [Argenziano et al. 1998] dermoscopic images of melanocytic skin lesions were studied to evaluate the incidence of 7 standard criteria. These features were selected for their frequent association with melanoma. Most of them were listed in the guidelines of the Consensus Meeting of Hamburg [Bahmer et al. 1990] and have been thoroughly described in step 2. See Table 1 for the definition of the 7 criteria.

The differences between melanomas and nevi were evaluated by a univariate statistical test and the significant variables were used for stepwise logistic regression analysis to determine their different diagnostic weight in the diagnosis of melanoma, as expressed by odds ratios. Using the odds ratios calculated with multivariate analysis, a score of 2 was given to the 3 criteria with odds ratios >5, termed “major” criteria, and a score of 1 to the 4 criteria with odds ratios <5, termed “minor” criteria. 

By a simple addition of the individual scores, a total score of 3 or more allowed classification for melanoma with a sensitivity of 95% and a specificity of 75%. In total 82% of melanocytic lesions were correctly diagnosed by the 7-point checklist method. See Table 2 for the score calculation.

Simplified scored pattern analysis

The 7-point checklist is a diagnostic method that requires the identification of only 7 dermoscopic criteria, thus enabling even less experienced clinicians to use the model following a relatively short learning curve. In fact this simplified algorithm has been shown to be reproducible with non-expert dermatologists, who were able to classify a high percentage of melanomas (sensitivity range: 85-93%) [Argenziano et al. 1998]. Of course the specificity rates of these non-experts were low (45-48%). This could be explained by the fact that most of the nonmelanomas in the test set were clinically atypical, easily leading to the decision of performing a biopsy. Clearly, the true specificity of the method in the daily routine should be much greater.

In conclusion, for a melanoma to be diagnosed, the identification of at least 2 melanoma-specific dermoscopic criteria (1 major plus 1 minor or 3 minor criteria) is required.

Table 1

The 7-point checklist: Definition and histopathologic correlates of the 7 melanoma-specific dermoscopic criteria
Criterion Definition Histopathologic
correlates *
  1. Atypical pigment network
Black, brown, or gray network with irregular meshes and thick lines Irregular and broadened rete ridgesd
  1. Blue-whitish veil
Confluent, gray-blue to whitish-blue diffuse pigmentation associated with pigment networkalterations, dots/globules and/or streaks Acanthotic epidermis with focal hypergranulosis above sheets of heavily pigmented melanocytes in the dermis
  1. Atypical vascular pattern
Linear-irregular or dotted vessels not clearly combined with regression structures and associated with pigment network alterations, dots/globules and/or streaks Neovascularization
  1. Irregular streaks
Irregular, more or less confluent, linear structures not clearly combined with pigment network lines Confluent junctional nests of melanocytes
  1. Irregular pigmentation
Black, brown, and/or gray pigmented areas with irregular shape and/or distribution Hyperpigmentation throughout the epidermis and/or upper dermis
  1. Irregular dots/globules
Black, brown, and/or gray round to oval, variously sized structures irregularly distributed within the lesion Pigment aggregates within stratum corneum, epidermis, dermo-epidermal junction, or papillary dermis
  1. Regression structures
White areas (white scarlike areas) and blue areas (gray-blue areas, peppering, multiple blue-gray dots) may be associated, thus featuring so-called blue-whitish areas virtually indistinguishable from blue-whitish veil Thickned papillary dermis with fibrosis and/or variable amounts of melanophages

 

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Table 2

 

The 7-point checklist: a minimum total score of 3 is required for the diagnosis of melanoma
ELM criterion Odds ratioa Seven-point scoreb
Major criteria:
1. Atypical pigment network 
2. Blue-whitish veil 
3. Atypical vascular pattern
5.19
11.1
7.42
2
2
2
Major criteria:
4. Irregular streaks
5. Irregular pigmentation
6. Irregular dots/globules
7. Regression structures
3.01
4.90
2.93
3.89
1
1
1
1

 

a Odds ratios measuring the capacity of each criterion to increase the probability of melanoma diagnosis. 
b The score for a criterion is determined on the basis of the odds ratio: >5 (score 2), and <5 (score 1).
Simply add the scores of each criterion that is present within a pigmented lesion

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References

  1. Argenziano G, Fabbrocini G, Carli P, De Giorgi V, Sammarco E, Delfino M. Epiluminescence microscopy for the diagnosis of doubtful melanocytic skin lesions. Comparison of the ABCD rule of dermatoscopy and a new 7-point checklist based on pattern analysis. Arch Dermatol. 1998;134:1563-1570.

  2. Bahmer FA, Fritsch P, Kreusch J, et al. Terminology in surface microscopy. J Am Acad Dermatol. 1990;23:1159-1162.

  3. Soyer HP, Smolle J, Hodl S, Pachernegg H, Kerl H. Surface Microscopy: a new approach to the diagnosis of cutaneous pigmented tumors. Am J Dermatopathol. 1989;11:1-10.

  4. Yadav S, Vossaert KA, Kopf AW, Silverman M, Grin-Jorgensen C. Histopathologic correlates of structures seen on dermoscopy (epiluminescence microscopy). Am J Dermatopathol. 1993;15:297-305.