Gastric Plasmacytoid Subtype Neuroendocrine Tumor

Abstract

A 76-year-old man presented to our institution for abnormal imaging. His complaint at the outside hospital was for abdominal pain. Evaluation included computed tomography (CT) which was notable for a gastric wall lesion of 28 mm in and serum tests revealed elevated gastrin level at >2000 raising concerns for gastrinoma. Esophagogastroduodenoscopy (EGD) was performed with endoscopic ultrasound (EUS). Findings were notable for a 27x25 mm hypoechoic submucosal lesion in the gastric antrum as well as separate 11x10mm gastric lesion. Additional EUS findings were left hepatic lobe hypoechoic area of 12x8mm concerning for metastatic lesion. Biopsies were taken via fine needle aspiration (FNA) and fine needle biopsy (FNB) of the larger antral mass and reviewed by on-site cytopathology and stains revealed chromogranin and synaptophysin positive but beta-catenin negative cells consistent with neuroendocrine tumor but more specifically a plasmacytoid cell neoplasm staged WHO Grade 1. Neuroendocrine tumors (carcinoid tumors) are often diagnosed based on staining with chromogranin A and synaptophysin being two of the four common positive stains. They are often divided into Gastroenteropancreatic Neuroendocrine Tumors (GEP-NET) and Pancreatic neuroendocrine tumors (PanNET). GEP-NET are often found in small intestine but more specific ileum. NETs associated with elevated gastrin level occur in 5% of gastric carcinoid tumors. NETs frequently metastasize to the liver. Treatment can consist of palliative surgery and sometimes chemotherapy in form of interferon, although gastrointestinal carcinoid tumors show 10-20% slow response to chemo. Overall survival for carcinoid tumors has increased from 2 years to 8 years.Figure 1