Non-invasive analysis of melanoma thickness by means of dermoscopy: a retrospective study

Epiluminescence microscopy (ELM), or dermatoscopy, is a non-invasive techni que for the diagnosis of cutaneous melanoma that may play a role in the non -invasive, preoperative assessment of melanoma thickness. This study invest igated the correlation between the frequency of appearance of some standard ELM criteria and the histological thickness of melanomas. In addition, the possible role of the total dermoscopic score (TDS) according to ABCD rule of dermoscopy as a predictor of melanoma thickness was analysed. The dermos copic images of 84 cutaneous melanomas were retrospectively investigated to evaluate the presence of 10 standard ELM criteria, and for each lesion the TDS was established (with observers blinded as to the tumour thickness). A statistically significant association was found between the presence of an irregular pigment network and melanomas with a Breslow index equal to or l ower than 0.75 mm (positive predictive value of 68%); in contrast, radial s treaming, atypical vascular pattern and grey-blue areas were associated wit h melanomas > 0.75 mm (positive predictive values of 77%, 65% and 70%, resp ectively). Of the melanomas thinner than 0.76 mm, 82% showed a TDS lower th an 6.80 (optimized cut-off point), while 79% of melanomas thicker than 0.75 mm had a TDS higher than 6.80 (chi2=30.815, P<0.001); the positive predict ive Value of a TDS,6.80 in the detection of lesions thicker than 0.75 mm wa s 79%. In conclusion, a statistically significant correlation does exist be tween some dermoscopic: features and melanoma thickness. Both the mostly us ed dermoscopic methods (standard ELM pattern analysis and the ABCD rule of dermatoscopy) may provide useful information in the non-invasive assessment of melanoma thickness. However, their diagnostic performance is far from 1 00%; further studies are needed to investigate whether the combination of d ermoscopy with other noninvasive approaches (e.g. sonometry) may result in an overall improvement in the diagnostic performance. (C) 2001 Lippincott W illiams & Wilkins.