Orbital Metastases of Neuroendocrine Tumors Treated With 177Lu-DOTATATE PRRT or 131I-MIBG Therapies.

Neuroendocrine tumors have a propensity to metastasize to the orbit, although the reason is unknown. A review of 251 neuroendocrine tumors treated with Lu-DOTATATE or I-MIBG at our institution since 2003 revealed 4 patients with orbital metastases (1.6%), 2 treated with Lu-DOTATATE and 2 with I-MIBG. Of these 4 patients, 1 patient was symptomatic with diplopia and eye pain, and 2 patients had physical signs of orbital involvement. The symptomatic orbital metastasis improved with Lu-DOTATATE therapy, and proptosis improved with I-MIBG therapy in 1 of 2 patients. We present the imaging findings of these 4 patients, as well as their management.