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 4 is a 72-year-old gentleman who was diagnosed with a well differentiated G2 metastatic ileal NET in 2006. He started monthly octreotide shortly thereafter in 2007. He was incidentally noted to have a left lateral rectus mass in March 2007 during a brain MRI. This lesion was monitored with serial MRI and remained stable until 2015 when it began to grow (Fig. c). The patient developed progressive diplopia and proptosis in 2015 which prompted an evaluation by radiation oncology. He received stereotactic radiosurgery (SRS) administered over 5 fractions to the site in February 2015 at VUMC and his diplopia and proptosis resolved within several months of treatment completion. He has unfortunately developed complications from his other sites of metastatic involvement including right sided nephrostomy tube placement from ureteral obstruction and an end colostomy due to recurrent small bowel obstructions from mesenteric tethering. His disease remains radiographically stable on his 68Ga-DOTATATE PET-CT from August 2018 (Fig. a and b).