Preoperative assessment of cutaneous melanoma thickness using 10-MHz sonography

Abstract

Objective: The purpose of this study was to evaluate the prognostic value of 10-MHz sonography in measuring melanoma thickness before biopsy or excision.

Subjects and methods: Fifty-four patients with lesions suggestive of melanoma participated in the study. Lesions were measured on sonography using a 10-MHz linear transducer before routine biopsy and histopathologic analysis. Sonographic measurements were compared with histopathologic results (Breslow index) using Pearson's correlation coefficient and concordance analysis. Additional statistical analyses included sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 10-MHz sonography in identifying lesions > 1 mm thick.

Results: Histopathologic analysis identified all 54 lesions as melanoma. On sonography, 34 lesions measured < or = 1 mm and 20 lesions, > 1 mm. Histopathologic analysis showed 32 lesions with a Breslow index of < or = 1 mm and 22 lesions with a Breslow index of > 1 mm. The median thickness of the 54 lesions was 1.33 mm (range, 0-5 mm) by the Breslow index compared with 1.85 mm (range, 0-4.8 mm) by sonography. Comparison of sonographic measurements and Breslow index values gave a correlation coefficient of 0.93 and a concordance coefficient of 0.99. Overall, sonographic measurements showed 86% sensitivity, 97% specificity, 93% accuracy, 95% positive predictive value, and 91% negative predictive value in identifying lesions with a Breslow index of > 1 mm.

Conclusion: In our series of 54 melanomas, 10-MHz sonography measured lesion thickness with good accuracy compared with histopathology. Sonography was effective in discriminating between tumors < or = 1 mm thick and those > 1 mm thick.