A 62-year-old man had a neuroendocrine tumor of the rectum treated by colon resection and radiation therapy. Three years later, he experienced diplopia and right periorbital swelling and also was found to have metastasis to the liver, lung, and groin. Indium-111 OctreoScan demonstrated a mass in the right orbit. Visual acuity was no light perception in the right eye (OD) and 20/30 in the left eye (OS). There was right eye proptosis of 10 mm on exophthalmometry and decreased ocular motility in all gazes. Magnetic resonance imaging (MRI) of the orbits revealed a 30-mm well-circumscribed intraconal mass adjacent to the medial rectus muscle displacing the optic nerve medially. The lesion was isointense on T1-weighted images with moderate enhancement after contrast. Enucleation and anterior orbitotomy were performed for the painful blind eye and tumor resection, respectively. Histopathology of the resected lesion showed metastatic neuroendocrine tumor with the tumor cells staining positive for chromogranin, synaptophysin, and neuron specific enolase. At 2 years follow-up, there was no orbital recurrence of the tumor; however, there was progression of the liver, lung, and skin metastases. Despite chemotherapy (carboplatin and TP-16) and external beam radiotherapy (EBRT) of extraorbital tumors, the patient died 3 years after orbital surgery.
A 64-year-old woman experiencing diplopia for 6 months was found to have a right orbital tumor on MRI. Three years before onset of eye symptoms, she had a colon carcinoid tumor treated by colectomy. Visual acuity was 20/20 OD and 20/40 OS. Ocular motility of the right eye was slightly limited in up and down gaze. MRI revealed a right orbital mass infiltrating the inferior rectus muscle and the resected lesion showed intermediate to large mononuclear cells with scant cytoplasm, irregular nuclei, and finely granular chromatin on histopathology, with positive staining for chromogranin, synaptophysin, pancytokeratin, and CD10, compatible with diagnosis of neuroendocrine tumor. MRI of the chest and abdomen revealed liver and lung lesions. She died 24 months after initial evaluation due to brain metastasis.