Orbital extension of choroidal melanoma: within a long posterior ciliary nerve.

Following enucleation, an epithelioid type of malignant choroidal melanoma involving the posterior pole was grossly and histologically found to exhibit direct extraocular extension along the emissary for the long posterior ciliary artery and nerve on the temporal side. In addition to a small tumor nodule on the outside of the sclera, melanoma extension was found up to the cut end in the otherwise well preserved ciliary nerve. After tenonectomy, additional extraocular melanoma extension in the core of this long posterior ciliary nerve was demonstrated for a total distance of 5 mm. As a result of the present findings, intraneural melanoma extension into the orbit by the way of a ciliary nerve has to be added to the other possible ways of direct extraocular melanoma extension.