Unusual presentation of metastatic neuroendocrine (carcinoid) tumor in the orbit

Abstract

Purpose: To report a rare presentation of metastatic neuroendocrine tumor in the orbit. Case report: A 43-year-old female presented with a left painful proptosis of 4 days duration associated with nausea and vomiting. There was a history of multiple liver metastases from an unknown primary carcinoid tumor for 7 years. Ocular examination revealed severe eyelid swelling associated with conjunctival injection, chemosis and complete external ophthalmoplegia. The visual acuity was 20/20 in right eye and no light perception in left eye. The initial clinical diagnosis was orbital cellulitis with optic nerve compression. Orbital imaging showed gross enlargement of left lateral rectus muscle with optic nerve compression consistent with a carcinoid metastasis. Surgical resection of the tumor mass along with the involved muscle was performed. Histopathology confirmed the diagnosis of neuroendocrine (carcinoid) tumor infiltrating fibro fatty tissue and skeletal muscle with widespread necrosis. On Immunohistochemical staining the tumor cells were positive for chromogranin A, synaptophysin and cytokeratin. Post-operative external beam radiotherapy (EBRT) and systemic chemotherapy were given. Conclusion: Acute necrosis in metastatic orbital carcinoid tumor can lead to orbital inflammation which could mimic orbital cellulitis. Systemic history and orbital imaging play an important role in differentiating the infective etiology from metastasis.