1218 Diagnostic performance for nail melanoma of melanin degradation products in the nail plate

Although dermoscopy is a viable diagnostic tool for nail apparatus melanoma (NAM) in clinical practice, the evaluation of image findings depends on subjectivity individual readers. To develop novel biomarker NAM, this study measured values pyrrole-2,3,5-tricarboxylic acid (PTCA; degradation product eumelanin), thiazole-2,4,5-tricarboxylic (TTCA; benzothiazole-type pheomelanin), and 4-amino-3-hydroxyphenylalanine (4-AHP; benzothiazine-type pheomelanin) plate to assess utility each substance. A total 86 samples from 37 fingers/toes (9 NAM: 4 men 5 women; average age, 64 [range: 25-86] years; 6 fingers 3 toes; 28 benign streaks [BNS]: 16 42 3-78] 19 9 toes) were collected 31 patients. The (range) substance (ng/mg) NAM 8.62 (1.79-26.30) PTCA, 4.94 (1.23-10.70) TTCA, 15.36 (1.34-81.20) 4-AHP, with mean PTCA 4-AHP both exceeding ng/mg. Among BNS fingers/toes, value at least 1 surpassed ng/mg only cases: cases developing childhood NAM-suspicious receiving follow-up. After excluding above cases, 22 1.55 (0.21-4.37) 0.90 (0.20-2.50) 0.68 (0.18-1.89) all which below sensitivity, specificity, positive predictive value, negative accuracy detecting 0.67, 1, 0.88, 0.44, 0.81, 0.84 0.56, 0.85, 0.87 respectively. Our results suggest that melanin products are potential biomarkers early detection.