Neuroendocrine Tumor (Carcinoid) Metastatic to Orbital Extraocular Muscle: Case Report and Literature Review

Diagnostic and Therapeutic Management of Primary Orbital Neuroendocrine Tumors (NETs): Systematic Literature Review and Clinical Case Presentation

BACKGROUND

The ocular involvement of neuroendocrine neoplasms (NENs) is uncommon and mainly represented by metastases from gastrointestinal and lung neuroendocrine tumors. Primary orbital NENs are even less common and their diagnostic and therapeutic management is a challenge.

METHODS

A systematic review of the literature was conducted from 1966 to September 2023 on PubMed to identify articles on orbital NENs and to summarize their clinical-pathological features, diagnosis and therapeutic management. Furthermore, we presented a case of a locally advanced retro-orbital primary neuroendocrine tumor that was referred to the certified Center of Excellence of Sant'Andrea Hospital, La Sapienza University of Rome, Italy.

RESULTS

The final analysis included 63 records on orbital NENs and 11 records focused on primary orbital NENs. The localization was mostly unilateral and in the right orbit; proptosis or exophthalmos represented the initial symptoms. The diagnostic work-up and therapeutic management was discussed and a diagnostic algorithm for the suspicion of primary orbital NENs was proposed.

CONCLUSIONS

A multidisciplinary approach is required for the management of primary orbital NENs, emphasizing the importance of early referral to dedicated centers for prompt differential diagnosis, tailored treatment, and an improved quality of life and survival.

Management of non-hepatic distant metastases in neuroendocrine neoplasms

Neuroendocrine neoplasms represent an uncommon disease with an increasing incidence. Thanks to improvements in diagnostic and therapeutic methods, metastases previously considered uncommon, such as bone metastases, or even very rare, such as brain, orbital and cardiac metastases, are more frequently found in daily practice. Due to the great heterogeneity of these neoplasms, there is a lack of high-quality evidence on the management of patients with these types of metastases. The aim of this review is to provide the current state of the art, reviewing neuroendocrine neoplasm specific studies and useful information from other tumor types and to propose a treatment recommendation with algorithms to consider in daily clinical practice.

Extraocular muscle enlargement

Extraocular muscle enlargement can occur secondary to a range of orbital and systemic diseases. Although the most common cause of extraocular muscle enlargement is thyroid eye disease, a range of other inflammatory, infective, neoplastic, and vascular conditions can alter the size and shape of the extraocular muscles. Imaging with computed tomography and magnetic resonance imaging plays an essential role in the workup of these conditions. This article provides an image-rich review of the wide range of pathology that can cause enlargement of the extraocular muscles.

Ocular adnexal manifestations of neuroendocrine neoplasms: a case report and a major review

PURPOSE

To describe a patient with orbital neuroendocrine neoplasm (NEN)/carcinoid tumor and to review the clinical presentation, systemic work-up, histopathologic features, and outcome of all previously reported ocular adnexal (OA) NENs.

METHODS

A systematic literature review. PubMed/MEDLINE and Google Scholar databases were searched for all well-documented cases of OA NENs.

RESULTS

Final analysis yielded 94 patients with OA NENs, 50 females (53%) and 44 (47%) males with an average age of 63 years (range 14-86). Of 91 patients with known information, the most common presenting signs were proptosis (56/91, 61%) and visual disturbances (42/91, 47%), induced by a mass most commonly associated with an extraocular muscle (49/63, 78%). The majority of tumors (88/94, 94%) were metastases, most commonly from the gastrointestinal tract (52/88, 59%). OA NEN metastasis presented following detection of primary tumor in 73/94 (78%) patients (median time to metastasis 36 months, range 0-288 months) and as an initial manifestation of disease in 15/94 (16%) patients (median time to primary detection 18 months, range 1-108 months). Systemic work-up included extra-OA NEN biopsy (37/54, 69%), multimodal imaging (42/54, 78%), and other laboratory studies (32/54, 59%). Resection with or without adjuvant chemotherapy, radiotherapy, and biologics was the most common intervention for OA NENs (36/82, 44%). Of 67 patients with available follow-up, the median survival was 108 months (95% CI 55-161 months) and the absolute 5-year survival rate was 68%.

CONCLUSIONS

OA NENs are almost exclusively metastases and can precede detection of primary tumor by many months, requiring appropriate diagnostic work-up.

Orbital metastasis from neuroendocrine tumour: Case report and literature review

Orbital metastases from neuroendocrine tumour are rare entities. An incidental finding of orbital metastasis originating from neuroendocrine tumour is presented in the context of a comprehensive review of all case reports and series published to date. Demographics, clinical features, diagnostic work-up, treatment and prognostic data from the published literature are discussed. Ninety-five patients with orbital metastases from neuroendocrine tumours have been reported so far. Average age at presentation is 63.8 years (range 25-86), with no significant gender predominance. Gastrointestinal tract is the most common site of primary neuroendocrine tumours (62-85%). Typical presentation includes proptosis (80-85%) and diplopia (27-62%) in patients with known primary neuroendocrine tumour elsewhere. Histological subtype and presence of metastases seem to be important prognostic factors. Incidental finding of neuroendocrine tumour mestastases in asymptomatic patients with unknown primary disease is uncommon. In such cases, orbital biopsy and structural and functional imaging are essential to establish a diagnosis and stage the disease.

Carcinoid Tumors of the Orbit and Ocular Adnexa

PURPOSE

Well-differentiated neuroendocrine or carcinoid tumors are found most commonly in the gastrointestinal tract. When metastatic to the orbit, they tend to have a propensity for the extraocular muscles. The purpose of this study was to better understand the diversity in presentation of orbital carcinoid disease and to determine predictors for survival.

METHODS

In this observational cross-sectional cohort study, data from 8 tertiary orbital practices were compiled. Demographic, clinical, pathologic, American Joint Committee on Cancer stage and grade, imaging, and management data were extracted for all the patients. Descriptive statistics were calculated. Subgroups were compared utilizing analysis of variance analyses and Kaplan-Meier curves. Time to progression and disease-specific and overall mortality were calculated. Comparisons were performed for the following a priori pairs: unknown versus known primary tumor, single versus multiple extraocular muscle involvement, unilateral versus bilateral orbital disease, extraocular muscle versus other orbital involvement, and excisional versus incisional surgery.

RESULTS

A total of 28 patients with carcinoid tumors of the orbit were identified. Of these, 57.1% of patients were female, the mean age at diagnosis of the primary tumor was 58.8 years and the mean age at diagnosis of orbital disease was 62.6 years. At primary presentation, all patients were American Joint Committee on Cancer stage III or IV and 21.4% demonstrated carcinoid syndrome. Muscle involvement was noted in 78.6% of patients, and of these, 72% were noted to have single muscle disease. Eight patients had no primary tumor identified; 3 of these 8 demonstrated disseminated disease at the time of diagnosis. The overall 5-year survival rate was 81.8% from diagnosis of primary tumor and 50% from diagnosis of orbital disease. Subgroup analysis revealed that patients with unilateral orbital disease when compared with bilateral orbital disease had a longer progression-free survival and time to death from all causes (p = 0.025). Patients with disease localized to the orbit at presentation had longer time to death than those with disseminated disease. Treatment with surgery, radiation, or octreotide did not appear to affect survival. Patients managed with systemic chemotherapy had a shorter time of survival than the rest of the group. All other subgroup comparisons were not found to be statistically significant.

CONCLUSIONS

Neuroendocrine tumors of the orbit represent a wide spectrum of disease, with some cases being part of disseminated disease, while others being localized presentations. This heterogeneity may be responsible for the slightly higher overall survival in these patients than others with metastatic carcinoid tumors in other locations.

Clinico-radiological findings of neuroendocrine tumour metastases to the orbit

Purpose: We present the clinico-radiological findings of neuroendocrine tumour metastases to the orbit.Methods: This was a multicentre, retrospective study of patients with neuroendocrine tumour metastases to the orbit. Data was collected from medical records across five different sites within Australia and the United Kingdom.Results: Nine patients (eleven lesions) were identified. The most common presenting complaint was diplopia (5/9, 56%). Disease occurred bilaterally in two patients. Seven patients (78%) had extraocular muscle involvement. The lateral recti (4/9, 44%) and superior recti (2/9, 22%) were the most commonly affected. Ocular presentation preceded primary tumour diagnosis in three patients (33%). On orbital imaging, metastases were most commonly reported as well circumscribed, ovoid or round, heterogeneous, contrast-enhancing masses. Features of intralesional haemorrhage and bony invasion are uncommonly reported.Conclusions: Neuroendocrine tumour metastasis to the orbit is uncommon. Metastases have a propensity for the extraocular muscles, commonly presenting as heterogeneous, well circumscribed, contrast-enhancing lesions on neuroimaging. New ocular symptoms, a history of neuroendocrine tumours, and these radiological findings, should lead to high clinical suspicion of metastatic disease. Atypical findings warrant biopsy to exclude other causes of orbital lesions.

Solitary late metastasis of primary renal cell carcinoid tumor to the extraocular muscles imaged with indium-111 octreotide

A 75-year-old male presented with right eye pain and proptosis. His history was significant for renal cell carcinoma treated with left nephrectomy 2 years previously. Computed tomography (CT) imaging demonstrated a 1.6-cm enhancing lesion in the right retrobulbar space. Surgical biopsy revealed a low-grade metastatic carcinoid tumor. At retrospective review, the primary renal lesion from 2 years prior was rediagnosed as consistent with a renal carcinoid tumor. Indium-111 octreotide single photon emission CT/CT imaging demonstrated a solitary metastasis within the right extraocular muscles. The patient subsequently developed additional metastases within the remaining right kidney and lung.

Orbital metastases from neuroendocrine neoplasms: clinical implications and outcomes

PURPOSE

Neuroendocrine neoplasms (NENs) may rarely metastasise to the orbit. Published data on epidemiology, incidence and preferred treatment is limited. We present the largest cohort of symptomatic and asymptomatic NEN patients with orbital metastases and data on epidemiological parameters, symptoms as well as diagnostic/treatment modalities used.

METHODS

We identified patients from our internal NEN database of patients who had also undergone Gallium⁶⁸-DOTATATE PET (Ga⁶⁸-DOTA). The diagnosis of orbital metastatic NEN was made on somatostatin receptor imaging and confirmed on a dedicated MRI of orbits.

RESULTS

We identified 27 patients of 994 patients evaluated with Ga⁶⁸-DOTATATE PET imaging during their surveillance monitoring in our department; 15 female, average age at NEN diagnosis 53 years and orbital metastatic NEN diagnosis 59 years. The majority of NEN primaries originated from small bowel (18/27, 66.4%) or pancreas 4/27 (4/27, 14.8%). Hepatic with or without concomitant skeletal metastases were present in 23/27 (85%) of patients. Ocular symptoms and/or signs were evident in 11/27 (41%) of patients. 5/11 symptomatic patients underwent external beam radiotherapy (EBRT) resulting in complete symptoms resolution. The 5-year survival was estimated at 84.1%.

CONCLUSIONS

Orbital metastases of NEN have a relatively low prevalence, more commonly associated with small bowel primary. Extraocular muscles are primarily affected, irrespectively of liver disease burden. Survival does not seem to be affected. EBRT is an efficacious treatment modality for both symptom relief and tumour growth control. Administration of peptide receptor radionuclide therapy may occasionally induce temporary ocular symptoms, which resolve following treatment with a short course of steroids.

Long-term Outcome in 7 Patients With Idiopathic Orbital Myositis

Purpose

Idiopathic orbital myositis, a rare disease of unknown cause, presents a diagnostic puzzle because the diagnosis is based on the exclusion of other diseases. This study aims at elucidating its long-term outcome to answer a clinical question whether idiopathic orbital myositis would be a distinct clinical entity.

Methods

Retrospective review was made on 7 consecutive patients (6 men and 1 woman) with the age at the initial visit ranging from 33 to 69 years (mean, 45.8 years) who were diagnosed with idiopathic orbital myositis and followed for 5 years or more (mean, 9.2 years) at a referral-based hospital.

Results

Chief complaint at the initial visit was diplopia in 4 patients, blurred vision in 2 patients, and proptosis in 1 patient. On magnetic resonance imaging, 4 patients showed enlargement of a single extraocular muscle on unilateral side while 3 patients showed enlargement of multiple extraocular muscles on unilateral side or bilateral sides. No patient developed systemic diseases or other orbital lesions in the long-term follow-up. All patients at the last visit were free from symptoms, including diplopia, after tapering of prednisolone at the initial dose of 20 to 60 mg daily.

Conclusion

Idiopathic orbital myositis had a favorable long-term outcome with corticosteroid administration and appears to be a distinct clinical entity without systemic involvement.

The eye of the beholder: orbital metastases from midgut neuroendocrine tumors, a two institution experience

BACKGROUND

Metastases 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 PRESENTATIONS

Patient 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.

CONCLUSIONS

NETs 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.

Incidental Orbital Neuroendocrine Metastases on 111In-OctreoScan and MRI

Neuroendocrine tumors have a propensity to metastasize, but rarely to the orbits. A 69-year-old woman with history of neuroendocrine tumor of pancreatic primary underwent routine follow-up In-pentetreotide (OctreoScan) imaging, with 24-hour whole-body planar images showing subtle right periorbital tracer uptake that localized to extraocular muscles on subsequent SPECT/CT. Orbital MRI further defined the location of these highly suspicious orbital metastases, which were treated with external radiation, with follow-up MRI showing decreased size of the orbital metastases. Early identification and treatment of orbital metastases is critical to help preserve vision and quality of life.

Metastasis to the extraocular muscles: a case report, literature review and pooled data analysis

Metastasis to the extraocular muscles (EOM) is rare. The existing literature comprises only of isolated case reports therefore a summative description of these lesions is lacking. This study presents a case of bilateral rectus muscle metastasis from malignant melanoma. Furthermore a literature review and pooled data analysis is undertaken with 43 articles encompassing 77 patients and 101 eyes. Mean age was 53 years, 54% were male, 66% had unilateral involvement and 34% had bilateral involvement. The primary malignancies were melanoma (n = 17, 22%), breast (n = 15, 15%) and carcinoid (n = 11, 14%). A single muscle was involved in 56 eyes (67%) and multiple muscles in 27 eyes (33%). Lateral rectus was most commonly affected (n = 44, 53%). Presenting symptoms included restricted eye movements (n = 48, 62%), proptosis (n = 45, 58%), diplopia (n = 27, 35%) and pain (n = 18, 23%). Scattered case reports have previously made it difficult to characterise this phenomenon thus a pooled data analysis is presented.

Primary renal carcinoid metastatic to the orbit

A 70-year-old man with a medical history of metastatic renal carcinoid tumor presented with several months of painless proptosis of the OS. The patient was receiving octreotide and everolimus chemotherapy. MRI revealed a well-circumscribed mass in the left lateral rectus muscle consistent with metastasis. Because the patient was asymptomatic, he was observed and maintained a stable amount of proptosis without diplopia or change in vision.

Genetic analysis of an orbital metastasis from a primary hepatic neuroendocrine carcinoma

A 71-year-old female with a known history of primary hepatic neuroendocrine carcinoma, presented with a visual defect, proptosis and restricted eye movements of the right eye. Biopsies from the orbit and from the primary hepatic neuroendocrine carcinoma showed similar morphological and immunohistochemical features, and high-resolution, array-based comparative genomic hybridization demonstrated loss of one copy each of chromosomes 3 and 18, and gain of 1q both in the primary hepatic neuroendocrine carcinoma and in the orbital tumour. The orbital mass was diagnosed as a metastasis from the primary hepatic neuroendocrine carcinoma. Primary hepatic neuroendocrine tumours are extremely rare, and the orbit is an extremely rare location for a neuroendocrine carcinoma metastasis. This is the first reported case of an orbital metastasis with origin from a primary hepatic neuroendocrine carcinoma.

Usual and unusual neuroendocrine tumor metastases on (68)Ga-DOTANOC PET/CT: a pictorial review

Neuroendocrine tumors (NETs) are slow-growing indolent tumors that often present with metastatic disease at the outset. They commonly metastasize to lymph nodes, liver, bone, and lungs. However, metastasis to other rare sites may occur. It is important to have clear knowledge of unusual NET metastatic sites because their presence may lead to a more directed investigation. Also, it will be helpful in ruling out incidental second malignancies that might be encountered. The objective of this pictorial article was to provide an illustrative tutorial showing the clinical utility of Ga-labeled somatostatin analog [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-octreotide (Ga-DOTANOC) PET/CT for imaging usual and unusual metastatic sites in patients with NETs.

Skeletal Muscle Metastases in a Patient With Neuroendocrine Tumor

Carcinoid tumors are rare but diverse group of malignancies that arise from neuroendocrine cells. Skeletal muscle metastasis is exceedingly rare and is associated with a poor prognosis. We report a case of carcinoid tumor of the ileocecal with skeletal muscle metastasis. We also review available case reports of carcinoid tumors metastasizing to the muscle.

Intramuscular metastases on FDG PET-CT: a review of the literature

OBJECTIVE

Intramuscular metastases (IM) are both rare and difficult to detect using routine anatomical computed tomography (CT) imaging. However, since the introduction of 18F-fluoro-deoxy-glucose (FDG) PET-CT, the number of detected IM has increased. We review the available literature to illustrate the relevance of these findings for staging and patient management.

METHODS

In a review of the literature, we found one series and 33 case reports of IM shown on FDG PET-CT. No cases were reported before 2005. Furthermore, we present a patient with nonsmall cell lung cancer and a solitary distant metastasis in the left musculus infraspinatus that was not detected on diagnostic CT, but was found on FDG PET-CT.

RESULTS

For a total of 39 recorded cases of IM, we found that FDG PET-CT had a significant impact on patient management in at least 51% of cases. Where reported, lesions were either isodense or hypodense on CT compared with the surrounding muscle tissue. The lesions that were also analyzed with MRI showed heterogeneous intensity. Five out of 39 patients had metastases in the extraocular muscles of one or both orbits.

CONCLUSION

FDG PET-CT appears to be a sensitive tool for detecting IM, with important impact on management in many cases.

Neuroendocrine tumors of the orbit--clinicopathological findings in 3 more cases of this rare entity and review of the literature

INTRODUCTION

Neuroendocrine orbital tumors are rare occurrences. They are poorly characterized histologically and a spectrum of different cell types exists. This short case series studies the various tumor morphologies as well as the patients' clinical profiles.

METHODS AND MATERIALS

Patients treated and followed up at the Singapore National Eye Centre over a period of 8 years from 1(st) January 2002 to 31(st) December 2009 were identified from the orbital tumor board results. The case notes of patients with the diagnosis of neuroendocrine tumors were analysed, and a review of the literature performed.

RESULTS

Three patients are described in this series. The history, clinical examination findings, imaging findings as well as tumor histology were described. The mean age was 63 years, and 2 patients were male. All presented with proptosis. Only one patient had systemic symptoms on presentation. All patients had surgical excision of the tumor and two had adjuvant radiotherapy of the orbit. Median follow-up period was 3.5 years.

DISCUSSION

Patients with a biopsy-proven diagnosis of orbital neuroendocrine tumors should be monitored even when systemic examination fails to identify peripheral disease. Such examination should always include a full endoscopic gastrointestinal review.