Dermatologists' accuracy in early diagnosis of melanoma of the nail matrix.
OBJECTIVE
To measure and compare the accuracy of 4 different clinical methods in the diagnosis of melanoma in situ of the nail matrix among dermatologists with different levels of clinical experience.


METHODS
Twelve cases of melanonychias (5 melanomas and 7 nonmelanomas) were presented following 4 successive steps: (1) clinical evaluation, (2) evaluation according to the ABCDEF rule, (3) dermoscopy of the nail plate, and (4) intraoperative dermoscopy. At each step, the dermatologists were asked to decide if the lesion was a melanoma.


METHODS
The test was administered at 2 dermatological meetings in 2008.


METHODS
A total of 152 dermatologists, including 11 nail experts, 53 senior dermatologists, and 88 junior dermatologists.


METHODS
The answers were evaluated as percentage of right answers for each diagnostic step according to the different grade of expertise. Differences among the percentage of right answers in the different steps were evaluated with the z test at a 5% level of significance. The agreement was investigated using Cohen kappa statistic.


RESULTS
The only method that statistically influenced the correct diagnosis for each category (experts, seniors, and juniors) was intraoperative dermoscopy (z test; P < .05). Cohen kappa statistic showed a moderate interobserver agreement.


CONCLUSIONS
Overall accuracy of dermatologists in the diagnosis of nail matrix melanoma in situ is low because the percentages of physicians who indicated the correct diagnosis during each of the first 3 clinical steps of the test ranged from 46% to 55%. The level of expertise did not statistically influence the correct diagnosis.
Di Chiacchio
Nilton
N
Departments of Dermatology, Hospital do Servidor Público Municipal de Sâo Paulo, Brazil.
Hirata
Sergio Henrique
SH
Enokihara
Mauro Yoshiaki
MY
Michalany
Nilceo S
NS
Fabbrocini
Gabriella
G
Tosti
Antonella
A
D000328:Adult; D002983:Clinical Competence; D003880:Dermatology / Q000193:education; D046169:Dermoscopy; D042241:Early Diagnosis; D006801:Humans; D008545:Melanoma / Q000473:pathology* / Q000601:surgery; D009260:Nail Diseases / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery