Aims/Objectives: Compare GEP assay prediction of 434 melanocytic lesions with dermatopathologist interpretation.
Methods: Sensitivity and specificity of assay were calculated based on disagreement of assay prediction with dermatopathologist interpretation. Histologic features were recorded in disagreeing cases.
Results: Eighty-five percent of lesions (369/434) had sufficient RNA for scoring. 74.2% 274/369 lesions were classified as “benign”, 11.9% (44/369) “indeterminate”, and 13.8% (51/369) “malignant”. 38/51 of lesions rendered “malignant” by dermatopathologists were classified “malignant” by assay (sensitivity = 74.5%). Lesions rendered by assay as “benign” but “malignant” by dermatopathologists were more likely to have rarer cytologic features. (13/51) lesions rendered “malignant” by dermatopathologists were classified by assay as “benign,” (4/13) or “indeterminate” (9/13). 270/318 lesions rendered “benign” by dermatopathologists were “benign” by assay (specificity = 84.9%). Of 44/369 “indeterminate” lesions, dermatopathologists rendered 9/44
