A 63-year-old man presented with diplopia, redness, and pain of his left eye of 4 weeks duration. He had a history of neuroendocrine tumor of the testicle treated by radical orchiectomy 13 years before presentation followed by metastasis to the ileum, which was treated with bowel resection. Visual acuity was 20/30 OD and 20/25 OS and exophthalmometry revealed 4 mm proptosis of the left eye with mild limitation of ocular motility in lateral gaze. An intraconal, well-circumscribed mass in the left orbit displacing the lateral rectus muscle laterally was noted on MRI []. Histopathologic evaluation following tumor excision revealed a low-grade atypical neuroendocrine tumor with positive staining for chromogranin, synaptophysin, neuron-specific enolase, and AE1/3 compatible with carcinoid metastasis. Between the next 4.5 years, the patient had three recurrences of the orbital carcinoid which were managed with EBRT, surgical excision, and eventually orbital exenteration after the MRI showed early erosion of orbital bones by the tumor and tumor extension into the maxillary bone [Figures and ]. Histopathology of the exenterated orbital lesion showed multinucleated cells with large hyperchromatic nuclei and seven mitotic figures in 10 high-power fields consistent with aggressive metastatic poorly differentiated neuroendocrine tumor. The patient also developed signs of carcinoid syndrome with carcinoid metastasis to the liver, kidney, and parotid gland. He was alive with systemic metastasis 4 years after initial presentation.\nThe clinical and pathological features as well as treatment methods and outcomes for each patient are summarized in .
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).