Indeterminate melanocytic proliferations of the conjunctiva.

PURPOSE The purpose of this study is to test the hypothesis that a subset of conjunctival melanocytic proliferations exists that cannot be reproducibly classified as benign, malignant, or indeterminate. METHODS Three groups of excisional biopsy specimens of conjunctival melanocytic proliferations were evaluated by 5 ophthalmic pathologists. These groups included lesions that were considered by the authors to represent benign (Group 1, n = 5), malignant (Group 2, n = 5) and indeterminate melanocytic proliferations (Group 3, n = 5). The panel classified the same sections in all 3 groups in a randomized, masked fashion, first without and then with a clinical history of patient age, sex and race. The kappa statistic (k) was used to quantify the degree of agreement among observers. RESULTS There was strong concordance among the panel for both Group 1 (benign, k = 0.76) and Group 2 (malignant, k = 0.70) melanocytic proliferations. There was no concordance of the panel for Group 3 (indeterminate) lesions (k = -0.045). The concordance for Groups 1 and 2 and lack of concordance for Group 3 lesions were independent of knowledge of clinical history of age, sex, and race. CONCLUSIONS A subset of melanocytic proliferations of the conjunctiva exists that cannot be reproducibly classified by pathologists as benign, malignant, or indeterminate.