An Unusual Case of Neuroendocrine Carcinoma of the Gastro-Esophageal Junction Complicated by Syndrome of Inappropriate Antidiuretic Hormone Secretion

Cancers of the esophagus tend to be aggressive with a poor prognosis. Neuroendocrine carcinoma (NEC) of the esophagus is very rare and currently does not have any established treatment regimens. This is in part due to its rare prevalence. This case report presents an unusual case of distal esophageal NEC, which was complicated by liver metastasis and paraneoplastic syndrome. A 56-year-old postmenopausal woman came with complaints of weight loss, pain in the epigastric region, and intermittent dysphagia to solids for three months. An endoscopy revealed a 2 cm x 1 cm ulceronodular lesion located at the gastroesophageal junction. The biopsy showed NEC on histological examination, and the immunohistochemistry was positive for multiple neuroendocrine markers. A positron emission tomography (PET) scan revealed a stage IV metastatic disease that had spread to the liver as well as gastrohepatic and peri-gastric lymph nodes. Subsequently, the patient received palliative intent chemotherapy with Etoposide and Cisplatin for four cycles, which resulted in a partial response. Due to this, she was advised four more cycles of chemotherapy, but after two cycles, she developed signs of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Following management with hypertonic saline, her health deteriorated, resulting in death within one year of diagnosis. NECs of the esophagus tend to be detected at later stages and show a worse prognosis and disease course than squamous cell carcinoma or adenocarcinoma of the esophagus. With improvements in investigation methods, an increase in the detection of NEC in the esophagus can be expected in the future. Early diagnosis can help overall survival and boost quality of life. Further research and clinical trials are needed to assess ideal treatment plans.