Increased diagnosis of thin superficial spreading melanomas: A 20-year study

• Published in: Journal of the American Academy of Dermatology 2012-09, Vol.67 (3), p.387-394
• Main Authors: Frangos, Jason E., MD, Duncan, Lyn M., MD, Piris, Adriano, MD, Nazarian, Rosalynn M., MD, Mihm, Martin C., MD, Hoang, Mai P., MD, Gleason, Briana, MD, Flotte, Thomas J., MD, Byers, Hugh R., MD, Barnhill, Raymond L., MD, Kimball, Alexa B., MD, MPH
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Dermatology; dermatopathology; Diagnosis, Differential; diagnostic drift; dysplastic nevi; Dysplastic Nevus Syndrome - epidemiology; Dysplastic Nevus Syndrome - pathology; epidemiology; Humans; Medical sciences; melanoma; Melanoma - classification; Melanoma - epidemiology; Melanoma - pathology; melanoma epidemic; Prevalence; Reproducibility of Results; Skin Neoplasms - classification; Skin Neoplasms - epidemiology; Skin Neoplasms - pathology; Tumors of the skin and soft tissue. Premalignant lesions
• ISSN: 0190-9622; 1097-6787
• DOI: 10.1016/j.jaad.2011.10.026

Background Diagnostic practice by dermatopathologists evaluating pigmented lesions may have evolved over time. Objectives We sought to investigate diagnostic drift among a group of dermatopathologists asked to re-evaluate cases initially diagnosed 20 years ago. Methods Twenty nine cases of dysplastic nevi with severe atypia and 11 cases of thin radial growth–phase melanoma from 1988 through 1990 were retrieved from the pathology files of the Massachusetts General Hospital. All dermatopathologists who had rendered an original diagnosis for any of the 40 slides and the current faculty in the Massachusetts General Hospital Dermatopathology Unit were invited to evaluate the slide set in 2008 through 2009. Results The mean number of melanoma diagnoses by the 9 study participants was 18, an increase from the original 11 melanoma diagnoses. A majority agreed with the original diagnosis of melanoma in all 11 cases. In contrast, a majority of current raters diagnosed melanoma in 4 of the 29 cases originally reported as dysplastic nevus with severe atypia. Interrater agreement over time was excellent (kappa 0.88) and fair (kappa 0.47) for cases originally diagnosed as melanoma and severely atypical dysplastic nevus, respectively. Limitations The unbalanced composition of the slide set, lack of access to clinical or demographic information, access to only one diagnostic slide, and imposed dichotomous categorization of tumors were limitations. Conclusions A selected cohort of dermatopathologists demonstrated a general trend toward the reclassification of prior nonmalignant diagnoses of severely atypical dysplastic nevi as malignant but did not tend to revise prior diagnoses of cutaneous melanoma as benign.