Neuroendocrine Carcinoma of Duodenum-an Uncommon Tumour at an Unusual Site

Anti-Hu-Associated Encephalomyelitis as a Presentation of Primary Extrapulmonary Small Cell Carcinoma of the Small Bowel: A Case Report

Small cell carcinoma (SCC) is a neuroendocrine tumor (NET) commonly found in the lung, known for rapid proliferation and early metastasis. Extrapulmonary small cell carcinomas (ESCC) are rare, with GI tract carcinomas exceedingly so. Due to the lack of clinical data on the treatment of ESCC, the standard regimen is the same as the SCC of the lung. Documented accounts of paraneoplastic encephalomyelitis associated with NETs are also uncommon. We present a patient who suffered from neurologic deficits before being diagnosed with paraneoplastic encephalomyelitis from a duodenal ESCC. The patient presented with ear pain and hematemesis. New symptoms arose after the resolution of initial symptoms, including shortness of breath and numbness. Autoimmune workup was positive for anti-Hu antibodies. A position emission tomography (PET) scan showed increased uptake in the duodenal region. Biopsy results from a duodenal ulcer revealed poorly differentiated neuroendocrine carcinoma with positive synaptophysin and strong positivity of Ki-67, consistent with ESCC. Numerous treatments, including platinum-based chemotherapy, yielded no neurologic improvement for the patient. This case details an atypical presentation of ESCC, which should be considered in patients suspected of paraneoplastic encephalomyelitis.

Transduodenal resection of periampullary neuroendocrine tumor: A case report

Introduction and importance

Periampullary tumors are characterized as tumors that emerge nearby to the major papilla in the duodenum. They are rare lesions with an incidence rate of 0.4–0.48 per 100,000. Neuroendocrine tumors (NETs) constitute only 3% of all duodenal tumors. Their proximity to the major and minor papillae along with the gastric outlet raises a surgical challenge.

Case presentation

Our patient is a 40-year-old, male, medically free. He presented with history of a testicular mass. A CT scan of the abdomen and pelvis was done and showed a large retroperitoneal lymph node. A biopsy of the epididymal mass showed no evidence of malignancy. Excision of the left para-aortic mass revealed a metastatic lymph node of a well-differentiated neuroendocrine tumor. Further evaluation by gallium-68 PET-CT scan showed a periampullary neuroendocrine tumor. The decision to operate was concluded in a multidisciplinary team meeting, and intraoperatively the duodenum showed a well-defined mass between the first and second part of the duodenum which was excised via a trans-duodenal submucosal approach. A frozen section confirmed a negative margin. The final histopathology report showed a grade 2 metastatic well-differentiated neuroendocrine tumor. The latest follow-up was 3 years post-op via fluorine-18 fluorodeoxyglucose PET-CT and it showed no FDG avid disease at the duodenum or pancreases with no FDG avid lymphadenopathy or distant metastasis.

Conclusion

Periampullary tumors that fall under certain parameters could be resected via transduodenal local resection. This procedure yields equivalent results to more invasive surgeries, such as a Whipple's procedure, with less morbidity.

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Ampullary neuroendocrine tumors (NETs) are rare in compare to duodenal NETs, as they are highly metastatic and aggressive regardless of the size.

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These tumors present a diagnostic challenge in addition to being a topic of contention regarding surgical resection options.

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The controversy resides in main surgical options; the first being a pancreaticoduodenectomy (PD), and the second is a transduodenal local resection.

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Certain conditions must be met to achieve a satisfactory outcome for transduodenal local resection in case of periampullary NETs.

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For patients who have met the criteria, transduodenal local resection is believed to be a less invasive, safe, and useful alternative for PD.

Gastrointestinal neuroendocrine tumors in 2020

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological, biological, and clinical characteristics that have increased in incidence and prevalence within the last few decades. They contain chromogranin A, synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor. Ki-67 index and mitotic index correlate with cellular proliferation. Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors. Most of the gastrointestinal neuroendocrine tumors are non-functional. World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm. Gastric neuroendocrine tumors arise from enterochromaffin like cells. They are classified into 4 types. Only type I and type II are gastrin dependent. Small intestinal neuroendocrine tumor is the most common small bowel malignancy. More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve. Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs. Duodenal and jejuno-ileal neuroendocrine tumors are distinct biologically and clinically. Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver. Appendiceal neuroendocrine tumors are generally detected after appendectomy. Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis. Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000. Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy, endoscopic ultrasound, serology of biomarkers, imaging studies and functional somatostatin scans. Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.