Dysplastic nevi can be diagnosed and graded reproducibly: a longitudinal study.

Abstract

Poor interobserver reproducibility in diagnosing and grading dysplastic melanocytic nevi is often cited as evidence against the ability of pathologists to recognize such an entity. We attempted to examine the diagnostic profiles of melanocytic lesions of two dermatopathologists in a stable population base. All 2600 melanocytic neoplasms were diagnosed at Stanford University Medical Center during the past 4 years by one dermatopathologist from 1987 to 1989 and a different dermatopathologist in 1990 and 1991. The two independently evaluated these lesions unaware of the other's criteria. The diagnostic profile of the two pathologists shows a striking degree of similarity: 76.7% versus 75.3% of all nevi were diagnosed as acquired melanocytic nevi, 8.8% versus 12.0% were diagnosed as mildly dysplastic, 7.0% versus 6.8% as moderately dysplastic, and 2.7% versus 1.6% as severely dysplastic. Our findings suggest that the two pathologists are using reproducible criteria for diagnosing and grading dysplastic nevi.