Incidental hydroxyapatite ocular implant uptake on bone scan done for prostate cancer staging: case report and brief review

A 74-year-old man recently diagnosed with high risk prostate cancer with high serum prostate specific antigen (PSA) was referred to nuclear medicine for a technetium-99m-methylene diphosphonate (Tc-99m MDP) bone scan. On delayed three-hour anterior planar image, an unexpected round focus of intense uptake was found overlying the right orbit. Single-photon emission computed tomography/computed tomography (SPECT/CT) localized the uptake to an ocular prosthesis. The hydroxyapatite composition of the ocular implant can be recognized by its bone-like density and its intense accumulation of 99Tc-MDP. Review of the patient’s history revealed remote right eye evisceration secondary to a complication of cataract surgery, consistent with the findings.