Nuclear and cytoplasmic features in the diagnosis of banal nevi, Spitz nevi, and melanoma.

BACKGROUND: Many authors have described cytologic features in a variety of melanocytic lesions but, to our knowledge, a statistical analysis of sensitivity, specificity, and overall accuracy of these features alone or in combination has not been performed.

OBJECTIVE: We sought to determine the diagnostic value of nuclear and cytoplasmic characteristics in the diagnosis of melanocytic lesions via multivariate statistical analysis.

METHODS: This is a retrospective observational study conducted on 300 melanocytic lesions. We evaluated a series of distinctive features; subsequently a multivariate model was used to determine sensitivity and specificity.

RESULTS: Major features that favor a diagnosis of melanoma include: pleomorphism with enlarged nuclei, mitotic figures, notching/corrugation of the nuclear envelope, and peppered moth nucleus. Features with intermediate value include: solid hyperchromasia, vesicular nucleus with single round nucleolus, and nuclear/cytoplasmic ratio greater than 4:1.

LIMITATIONS: Limitations of this study include its retrospective nature, and the reliance on the original diagnostic classification of each neoplasm.

CONCLUSION: Our data suggest that some nuclear alterations have greater value in the diagnosis of benign and malignant melanocytic lesions.