The dermoscopic (7FFM) versus the clinical (ABCDE) diagnosis of small diameter melanoma.

The diagnosis of small diameter melanoma, that is early melanoma, is particularly difficult. For this reason we decided to evaluate the improvement given from our diagnostic dermoscopic method 7FFM to the clinical diagnosis, ABCDE rule, of small diameter melanoma. A retrospective study evaluating the clinical and the dermoscopic slides of 76 small diameter melanomas observed from January 1 1993 to December 31 1998, and of 524 small melanocytic nevi consecutively observed from September 1 1997 to September 30 1999, has been undertaken. The sensitivity and the specificity of the ABCDE rule and of our diagnostic dermoscopic method 7FFM in the diagnosis of small diameter melanoma have been calculated. The difference of diagnostic power between the two methods has been calculated with chi square test. The sensitivity and the specificity of the ABCDE rule in the diagnosis of small melanomas were 47.3% and 56%, while the sensitivity and the specificity of our method 7FFM were 68.8% and 86%. The difference of diagnostic power between the two methods was statistically significant: P<0.01 for both sensitivity and specificity. The sensitivity of the two methods together was 81.5% while the specificity of the two methods together was 50.6%. Our results show that our diagnostic dermoscopic method 7FFM improves both sensitivity and specificity in the clinical diagnosis of small diameter melanomas. Anyway the clinical and the dermoscopic diagnosis are not mutually exclusive as the best sensitivity is obtained with the two methods together.