Combined nevi of the conjunctiva.

PURPOSE To report the clinical and histologic features of combined nevi of the conjunctiva, a type of nevus that is not uncommon in the skin but has rarely been reported in the conjunctiva. METHODS Conjunctival nevi and melanomas from the files of the University of California, San Francisco, eye pathology laboratory were reviewed from 1984 to 1999 for the presence of features of both standard nevocytic nevi and blue nevi. Clinical histories and, when available, clinical photographs were obtained. RESULTS Thirty-one combined nevi were discovered during the 15-year period between 1984 and 1999. One case before 1984 had been incorrectly diagnosed as a junctional nevus. The dendritic and spindle-shaped blue nevus cells had been overlooked because they were not recognized as distinct from the standard nevocytic nevus cells. The recognition of a blue as well as a brown color, a deep as well as a superficial component in the lesion, or a history of pigmentation since birth may help to establish the correct clinical diagnosis and prevent an unnecessarily deep surgical resection. Although growth of the lesion or "satellites" in some patients may favor a clinical diagnosis of melanoma, none of the lesions in this series were malignant. CONCLUSION Despite a paucity of reports of combined nevi of the conjunctiva in the medical literature, this type of nevus--a combination of a nevocytic and a blue nevus--is common and has been overlooked in the past.