Pseudouveitis with pancreatic carcinoma: a case study
Overview of the Study
This study is a report of a case of a 61- year- old man who presented with progressive deterioration of general condition with unilateral recurrent episodes of pseudouveitis presenting as non- granulomatous panuveitis of the left eye related to a choroidal metastasis.
Neuroendocrine tumors are tumors known for their heterogeneity and their extensive malignant potential that tend to have a relatively prolonged course. They are tumors that metastasize rarely to their orbit. The researchers believe that ocular metastases from pancreatic neuroendocrine tumors (PNETs) have never been reported in the literature.
His histopathological analysis and radiological imaging suggest the diagnosis of metastatic pancreatic neuroendocrine carcinoma as the primary tumor. Choroidal metastases from neuroendocrine tumors are very rare but compromise patients’ well-being because of visual impairment. Rarely, these metastases can be the first manifestation of unknown tumors, warranting further investigations to detect primary cancer.
Pancreatic neuroendocrine tumors
Pancreatic neuroendocrine tumors are a type of heterogeneous group of tumors that arise from the endocrine tissues of the pancreas. They make up only around 1%– 2% of pancreatic tumors. Due to the improvement and widespread use of diagnostic imaging, their incidence has significantly increased.
These tumors are often classified as functional or non-functional tumors depending on the presence of clinical syndrome caused by the hypersecretion hormones, and in most cases, they are non-functional. The aggressiveness of these tumors is very unpredictable ranging from slow-growing to invasive forms. Metastasis commonly affects the liver, lymph nodes, and bones. Ocular metastases and pseudouveitis from neuroendocrine tumors are exceedingly rare and can simulate other primary or metastatic lesions.
Non-functional PNETs (NF- PNETs) comprise up to 90% of all PNETs and are often asymptomatic. The lack of hormonal syndromes makes clinical symptomatology discrete and non-specific. As a result, these tumors are most often diagnosed later during the course of the disease, revealing signs of local invasion or distant metastasis. In fact, 32%–73% of NF- PNETs are metastatic at the moment of diagnosis.
The most common area of metastasis is the liver. Other sites including bones, spleen, peritoneum, and brain have been reported. Several studies had shown that ocular metastases are reported to be the most common intraocular malignancy, even more, frequent than primary uveal melanoma, occurring through hematogenous spread by carotid and ophthalmic artery.
The prevalence of metastasis estimated from post-mortem examination ranged from 4% to 10% with a clear predominance of the choroid because of its rich vascular supply. The most frequently found primitives are lung and breast cancers.
Uveal metastasis from neuroendocrine tumors has only rarely been reported and rarer from pancreatic ones. In a series of 410 patients with uveal metastases, the primary cancer was a neuroendocrine tumor in only 9 cases (2.2%).
The site of the primary neuroendocrine tumor was the bronchial tract in seven patients, the esophagus in one, and the thymus in one. Classically, the diagnosis of ocular metastases is evoked in case of a prior history of malignancy. However, these metastases can rarely be diagnosed prior to the detection of the primary tumor.
In 230 consecutive autopsies of patients who died of cancer of all types, Bloch and Gartner found a 12% incidence of ocular involvement. In another small series of15 cases of ocular carcinoid metastasis, the primary neoplasm was unknown and clinically silent in three cases. Data regarding survival after the diagnosis of ocular metastases of neuroendocrine tumors is limited.
These findings suggest that patients with neuroendocrine tumors may have prolonged survival despite metastatic dissemination. Early diagnosis and appropriate treatment in order to preserve their vision and quality of life are crucial.
Case Study: Pseudouveitis
This case is of a pancreatic neuroendocrine carcinoma revealed by choroidal metastasis. The patient was a 61-year-old non-smoker male with a 5-year history of diabetes mellitus type 2. He was treated with Metformin and basal insulin. He complained of recurrent eye redness, ocular pain, and a progressive decrease in visual acuity of the left eye. His eye problems were progressing for 6 months. His health was also deteriorating and had a significant weight loss of 30kg in 6 months.
His physical examination results were normal. The patient was afebrile with normal vital signs. No general symptoms were found, no meningeal syndrome, or cutaneous eruption. His biological parameters were also normal.
Ophthalmological examination showed decreased visual acuity with 8/10 vision on the right eye and 3/10 vision on the left. There were features of-granulomatous panuveitis: left anterior pseudouveitis with hypopyon, posterior iris synechia, and dense diffuse vitreous without retinal detachment. The right eye was quiet, with no evidence of intraocular inflammation.
Orbital ultrasonography showed circumferential left choroidal echogenic and heterogeneous tissue thickening suggestive of metastases. Thoracic- abdominopelvic computed tomography was performed in order to search primary neoplasm. An invasive heterogeneous tumor mass at the level of the pancreatic body measuring 48 × 36 mm, with upstream pancreatic atrophy and marked dilatation of the Wirsung duct was detected.
Multiple nodules disseminated through liver parenchyma, and hypodense without bile duct dilatation were also noted. The histopathology report of the CT-guided biopsy showed a largely necrotic carcinomatous proliferation organized in trabecular structures.
Tumor cells were rounded or polyhedral, with eosinophilic cytoplasm, large vesicular nuclei, and highly irregular nuclear contours. On immunohistochemical analysis, tumor cells stained diffusely for chromogranin and synaptophysin. The Ki67 showed a proliferative index of 30% confirming the diagnosis of pancreatic neuroendocrine carcinoma. A chemotherapy regimen as an initial treatment based on a combination of etoposide (VP16) and cisplatin (CDDP) was planned.
Treatment
Numerous therapeutic modalities are proposed including beam radiotherapy, systemic chemotherapy, and surgical excision. External irradiation is an efficient treatment for orbital metastases that improves visual acuity.
It is especially useful for symptomatic patients with single lesions. However, data regarding the response of uveal carcinoid metastases after palliative radiation is not available. Chemotherapy has also proven its efficacy in several cases. The authors recommended the use of cisplatin and etoposide in the treatment of aggressive metastatic neuroendocrine carcinoma.
Moreover, the combination of chemotherapy and radiotherapy seems to be an efficient therapeutic option. In a series of six patients with ocular metastases from carcinoid tumors, treated with chemotherapy and external radiation, all patients responded well to that treatment and did not require surgical excision.
In many studies, chemotherapy has been considered to be equally as effective as radiation therapy for the treatment of ocular metastasis based on clinical lesion regression and improved visual acuity.
Conclusion
Pseudouveitis and choroidal metastases from neuroendocrine tumors are extremely rare. They also affect the patient’s well-being through visual impairment. To enhance the quality of life, early diagnosis and treatment should be prioritized. This case serves as a reminder that unilateral recurrent pseudouveitis should be well explored with orbital ultrasound or ideally magnetic resonance imaging and that identification of orbital metastases warrants further investigation to detect the primary tumor.
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