Foreign-Body Giant-Cell Reaction to the Hydroxyapatite Orbital Implant

Porous, coral-derived hydroxyapatite, a bone graft substitute, has recently been used as an orbital implant after enucleation. The implant is enveloped with a scleral shell to allow attachment of the extraocular muscles and greater movement in the orbit.1,2After implantation, the hydroxyapatite is infiltrated with fibrovascular tissue, which minimizes extrusion and infection.1,2This technique is gaining popularity because of the improved appearance of the patient and increased mobility of the implant.2,3To our knowledge, only one report has been published about the histopathologic characteristics of the hydroxyapatite after implantation in a patient's orbit; it described mild histologic reaction to the hydroxyapatite.3We observed a moderately intense foreign-body giant-cell reaction in an orbital hydroxyapatite implant that was removed 19 days after implantation. Report of a Case. —A 9-year-old boy underwent enucleation of his right painful, blind eye. A 20-mm, hydroxyapatite spherical implant was wrapped around with preserved