BackgroundMetastases to the orbit occur rarely in midgut neuroendocrine tumor (NET) patients with only 20 cases reported to date. Patients typically present with bilateral involvement of the recti muscles and experience symptoms such as diplopia, proptosis, and decreased vision. Although orbital MRI remains the gold standard for imaging orbital disease, many orbital lesions are now detected on somatostatin-receptor (SSTR) based imaging such as 68Ga-DOTATATE PET-CT.Case presentationsPatient 1 is a 72 year-old female with a well-differentiated G3 ileal NET who was incidentally diagnosed with orbital metastases during a hospitalization for pre-septal cellulitis in 2018. Her disease has been controlled with capecitabine rather than local therapy.Patient 2 is a 68 year-old male with a G2 ileal NET who was diagnosed with orbital involvement after developing left peri-orbital swelling in 2017. He was found to have bilateral rectus muscle involvement and was treated with image-guided radiation therapy (IGRT) to both orbits and achieved disease control.Patient 3 is a 63 year-old female with a well-differentiated G3 ileal NET who was incidentally diagnosed with bilateral orbital masses in her recti after undergoing a 68Ga-DOTATATE PET-CT in 2015. She was asymptomatic initially however has now developed diplopia. She will be starting 177Lu-DOTATATE peptide radionuclide receptor therapy (PRRT) shortly.Patient 4 is a 72 year-old male with a grade 2 ileal NET who was incidentally diagnosed with a left lateral rectus metastasis in 2007. This was monitored via surveillance MRI until it began to grow and became symptomatic in 2015. The patient received stereotactic radiation to the site and has been asymptomatic since.Patient 5 is a 61 year-old female with a grade 2 ileal NET who developed progressive diplopia in 2016. Bilateral orbital metastases were noted on orbital MRI and she completed IGRT to the sites shortly thereafter. In the setting of continued growth of the masses she was switched to chemotherapy with capecitabine which has controlled her orbital disease.ConclusionsNETs can metastasize to the orbits. Orbital disease now often is detected on SSTR-based imaging rather than orbital MRI; when found, it changes treatment approach and surveillance for patients.

Introduction. Immune-related adverse event (IRAE) onset may represent a clinical biomarker for anti-programmed cell death protein 1 (PD-1) antibody response based on emerging evidence from patients with various advanced malignancies. This phenomenon has not been previously reported in a multidisease cohort of patients with gastrointestinal (GI) cancer with Food and Drug Administration (FDA)-approved indications to receive immune checkpoint inhibitor therapy. Materials and Methods. The study was a multicenter retrospective cohort analysis of 76 patients with GI cancer who had received anti-PD-1 antibodies for FDA-approved indications. The primary and secondary outcomes of the study were progression-free survival (PFS) and overall survival (OS) in patients based upon IRAE presence, respectively. PFS and OS were estimated by the Kaplan-Meier method; a Cox proportional-hazards model adjusted for IRAE onset, patient age, and enrolling institution was used to analyze outcomes.

Carcinoid heart disease is a devastating paraneoplastic consequence of unchecked hormone production from neuroendocrine tumors (NET) and often results in right-sided heart failure. While it occurs frequently in NET patients with carcinoid syndrome, cardiac metastases occur much less often and are usually only incidentally found. Gallium-68 dotatate (ga-68) is an imaging tracer which binds to somatostatin receptor 2 with greater avidity than Indium-111, the tracer used commonly in octreotide scans. Ga-68 PET/CT is the most sensitive study for detecting occult NET metastases and has emerged as the current imaging gold standard. We describe two cases from Vanderbilt University Medical Center and Stanford University Medical Center where asymptomatic patients with well-differentiated midgut NET were diagnosed with intra-cardiac metastases using ga-68 PET/CT. Management of these patients was altered based on the findings as they underwent extensive cardiac evaluation and initiation of therapy with octreotide. Fortunately, they have not suffered life-threatening cardiac complications seen in some NET patients, from other published series, such as bradycardia, heart block, syncope and arrhythmias. These possibilities suggest early cardiology evaluation and consideration of other therapies beyond octreotide, such as surgery or PRRT, may be essential for all NET patients found to have intra-cardiac metastases.