Neuroendocrine tumors are rare neoplasms that infrequently metastasize to the orbit. Given that patients with these tumors may have prolonged survival despite dissemination, maintaining quality of life by providing early diagnosis and effective treatment to preserve vision and comfort is a fundamental issue. We report the case of a 79-year old woman who presented with well-differentiated metastatic neuroendocrine tumor to the liver with no carcinoid syndrome and was started on intramuscular long-acting octreotide with disease stabilization. Two years later she developed right-sided diplopia associated with mild eye discomfort, proptosis and reddening. An magnetic resonance imaging showed a 2.1 cm mass in the right orbit and further biopsy confirmed a neuroendocrine tumor metastasis. The patient was treated with a four-week course of stereotactic radiotherapy to the right orbital metastasis (4000 cGy in 20 fractions) with minor conjunctivitis as the only side effect. Eighteen months later, she remains well with no visual loss.
Keywords: Carcinoid tumor; Diplopia; Neuroendocrine tumor; Orbital metastases; Radiotherapy.