Immunohistochemical staining techniques of intraocular tumors.

The peroxidase-antiperoxidase staining technique for the antigens S-100, neuron-specific enolase, and alpha 1-antichymotrypsin (alpha 1ACT) was applied to 57 intraocular tumors: 46 malignant melanomas of the uvea, seven retinoblastomas, and four tumors metastasizing to the eye. The staining characteristics of the different intraocular tumors were compared. Staining for S-100 in a fine-needle aspiration biopsy sample taken from a malignant melanoma of the choroid before enucleation of the globe was attempted. The positive staining of a few cells thus obtained suggested that this technique may be helpful in the diagnosis of melanomas. The alpha 1ACT stain used in this study has not been used previously in ophthalmology to our knowledge. We found 60% of malignant melanomas of the choroid stained positively. Another finding was the staining of the retinal pigment epithelium with alpha 1ACT in 30% of eyes with malignant melanoma of the uvea.