Figure 4.

More than 90% of distant metastases in prostate cancer patients are found in the bones. The axial skeleton is the most commonly affected (1). Although the osseous metastases are common in prostate cancer, orbital metastases are very rare. Adenocarcinoma of the prostate is implicated in 3.6% to 4% of all orbital metastases (6). Cranial and orbital MRI was performed on 84-year-old patient with castrate-resistant prostate cancer (PSA 17 ng/mL) who developed diplopia and proptosis in the right eye. ⁶⁸Ga PSMA PET/CT was performed upon seeing a periorbital mass in the MRI. Pathological PSMA involvement (SUV_max: 19.4) was observed in the lesion, approximately 3.5x2.5 cm in size, located in the sphenoid bone in the right and invading the temporal lobe, maxillary sinus and orbit (arrow). ⁶⁸Ga PSMA PET/CT also demonstrated multiple cervical, abdominal and pelvic nodal involvement and sclerotic skeletal metastases. 7400 MBq ¹⁷⁷Lu PSMA radionuclide therapy was administered to the patient. He did not have any side effects during treatment or in the following weeks. The patient died from posttraumatic intracranial bleeding during follow-up.