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 5 is a 61-year-old female who was diagnosed with a well differentiated G2 (Ki-67 5%) metastatic small intestine (not otherwise specified) NET in February 2010. She remained symptom free until April 2014 when she was started on monthly octreotide. In the setting of progressive disease, she subsequently received sunitinib and everolimus. She began to develop progressive diplopia and right ocular pain in August 2016. This prompted an orbital MRI which revealed bilateral recti masses in the right lateral and superior left medial muscles. She was evaluated by radiation oncology shortly thereafter and was treated with IGRT to 52Gy, which completed in October 2016. Although her right ocular pain improved, she had persistent diplopia. Her post-treatment orbital MRI in January 2017 revealed a mild increase in size of her right lateral rectus mass (Fig. a). She was then started on capecitabine in January 2017 on a two week on, one week off regimen schedule. Patient also established care with ophthalmology at this time. She achieved stable disease in her orbits with symptomatic improvement and did not demonstrate any evidence of visual field deficits. She continues capecitabine and her last MRI in July 2018 revealed ongoing shrinkage of her right lateral rectus mass (Fig. b); her recent 68Ga-DOTATATE PET/CT from October 2018 shows residual SSTR avidity within her bilateral recti muscles (Fig. c and d).