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.
Patient 2 is a 68-year-old male who was initially diagnosed with a well-differentiated G2 (Ki-67 10%) metastatic ileal NET in 2012. Post-resection of his primary, the patient began treatment with octreotide. Eventually, he enrolled on a clinical trial with 177Lu-DOTATATE PRRT. During a hospitalization in November 2017, while admitted for abdominal pain, he developed left peri-orbital swelling. This prompted an orbital MRI which demonstrated bilateral extraocular masses in his recti muscles (Fig. a). A subsequent biopsy confirmed metastatic NET. To manage his acute periorbital swelling, he was first treated with corticosteroids and later completed image-guided radiation therapy (IGRT) to 44 Gy to bilateral orbits in December 2017. The patient had a post-treatment MRI scan which demonstrated a decrease in signal abnormality and enhancement in the previously visualized lesions (Fig. b). Post-radiation, patient continued octreotide until his death in February 2018 due to progressive disease.