Orbital metastasis from neuroendocrine tumour: Case report and literature review

Orbital metastases from neuroendocrine tumour are rare entities. An incidental finding of orbital metastasis originating from neuroendocrine tumour is presented in the context of a comprehensive review of all case reports and series published to date. Demographics, clinical features, diagnostic work-up, treatment and prognostic data from the published literature are discussed. Ninety-five patients with orbital metastases from neuroendocrine tumours have been reported so far. Average age at presentation is 63.8 years (range 25-86), with no significant gender predominance. Gastrointestinal tract is the most common site of primary neuroendocrine tumours (62-85%). Typical presentation includes proptosis (80-85%) and diplopia (27-62%) in patients with known primary neuroendocrine tumour elsewhere. Histological subtype and presence of metastases seem to be important prognostic factors. Incidental finding of neuroendocrine tumour mestastases in asymptomatic patients with unknown primary disease is uncommon. In such cases, orbital biopsy and structural and functional imaging are essential to establish a diagnosis and stage the disease.