Table 1. Dermoscopic Characterization of SK-like Melanomas and Interobserver Agreementa.
| Dermoscopic Features | Total, No. (%) (N = 134) |
Interobserver Agreement, κ Valueb |
Concordance Between Both Readers: Positive Agreement, %/Presence According to Both Readers, % |
|---|---|---|---|
| General characteristics | |||
| Melanoma diagnosis on overall dermoscopic evaluation | 110 (82.1) | 0.41 | 88.1/77.6 |
| SK diagnosis on overall dermoscopic evaluation | 24 (17.9) | 0.41 | 62.5/7.5 |
| Symmetry | 47 (36.7) | 0.30 | 25.5/9.4 |
| Asymmetry in 2 axes | 44 (34.4) | 0.31 | 90.9/31.3 |
| Palpable or raised | 89 (66.4) | 0.45 | 92.1/61.2 |
| Ulceration | 25 (18.7) | ND | |
| Melanocytic features | |||
| Pigment network | 74 (55.2) | 0.69 | 87.3/46.3 |
| Atypical pigment network | 66 (49.3) | 0.50 | 79.6/32.1 |
| Facial pseudonetwork | 16 (11.9) | ND | |
| Negative network | 11 (8.2) | ND | |
| Pigmented globules and dots | 68 (50.7) | 0.50 | 69.7/46.3 |
| Irregular globules and dots | 64 (47.8) | 0.47 | 67.1/41.0 |
| Pseudopods or streaks | 47 (35.1) | 0.70 | 83.7/26.9 |
| Blotches | 44 (32.8) | 0.40 | 54.1/24.6 |
| Blue-white veil (raised area) | 72 (53.7) | 0.66 | 87.7/42.5 |
| Blue-black sign | 43 (32.3) | 0.50 | 59.0/27.1 |
| Blue gray regression | 39 (29.1) | ND | |
| Shiny white structures | 49 (36.6) | 0.47 | 49.0/17.9 |
| SK features | |||
| Sharply demarcated borders | 86 (64.7) | 0.12 | 38.4/24.8 |
| Comedo-like openings | 41 (30.6) | 0.50 | 70.6/18.0 |
| Fissures and ridges | 15 (11.2) | ND | |
| Cerebriform-like pattern | 6 (4.5) | ND | |
| Network-like structures | 12 (9) | ND | |
| Yellowish keratin | 42 (31.3) | 0.44 | 60.0/20.1 |
| Scale and hyperkeratosis | 45 (33.6) | 0.51 | 56.3/33.6 |
| Milia-like cysts | 30 (22.4) | ND | |
| ≥3 Milia-like cysts | 17 (12.7) | ND | |
| Mouth-eaten border | 6 (4.5) | ND | |
| Fingerprint-like areas | 4 (3.0) | ND |
Abbreviations: ND, not done; SK, seborrheic keratosis.
Dermoscopic description is shown according to observer 1, an independent blinded expert who evaluated the 134 cases. Interobserver agreement between the 2 observers (both experts in the field [S.S. and P.A.]) was assessed for criteria presented in at least 30% of the 134 cases, according to observer 1 and is expressed as κ values, the percentage of positive concordance for each feature, and the percentage of the total series where both observers found the criteria.
The κ values were assessed for features observed in at least 30% of cases. Meaning of the level of agreement depending on κ value ranges: 0.01 to 0.20, slight agreement; 0.21 to 0.40, fair agreement; 0.41 to 0.60, moderate agreement; 0.61 to 0.80, substantial agreement; 0.81 to 0.99, almost perfect agreement.