“ Carcinoid tumors of the gastrointestinal tract are a biologically heterogeneous group of tumors with a spectrum ranging from benign indolent tumors to aggressive metastatic malignancies.” Imaging Features of Carcinoid Tumors of the Gastrointestinal Tract Ganeshan D et al. AJR 2013; 201:773-786
Carcinoid Tumors: Clinical Presentation - Incidental finding on CT or endoscopy - Carcinoid syndrome - Bowel obstruction - Perforation - Intussusception - Bowel ischemia - GI Bleeding - Fact: symptoms will vary depending on site of primary (i.e. vomiting common in gastric carcinoid and rectal pain and bleeding in colonic carcinoids)
Gastric Carcinoid Tumors: Facts - 12% of GI Carcinoid (NETS) tumors - Four types of tumor with type 1 most common (70-80%) and seen in middle aged woman. - Type 1 is associated with chronic atrophic gastritis and usually in gastric fundus or body. The lesion are usually under 1 cm and submucosal in origin - Type 2 are least common (5-10%) and is usually multicentric and small and associated with Zollinger Ellison Syndrome
Gastric Carcinoid Tumors: Facts - Type III account for 15-25% of gastric NETs and are usually > 2 cm in size. These are more aggressive are frequently metastasize - Type III often present as a large mass with liver metastases - Differential dx for type III lesion is adenocarcinoma, lymphoma, and GIST tumors - Differential dx for type I and II lesions include polyps, Kaposi’s sarcoma, metastases (melanoma and RCC), early adenocarcinoma, glomus tumors
CT of GI Carcinoid Tumors: Facts - Metastases more common from small bowel NETs than from colonic NETs - Tumors over 2 cm commonly metastasize and tumor over 2 cm do not usually - Liver metastases are usually hypervascular but may be hypovascular in up to 20% of cases
CT Findings - Submucosal mass or masses - Usually 1-4 cm - Can mimic gastric polyps - May have associated gastric fold thickening due to elevated gastrin levels.
Gastric Carcinoid - Originate from Kulchitsky cells in the crypts of Lieberkuhn - Cytoplasm contains eosinophilic granules that have an affinity for solver stain (argenaffinomas) - < 35% of GI carcinoids are located in stomach - Most are in distal antrum
Gastric Carcinoid Rare but recognized complication of prolonged severe hypergastrinemia chronic atrophic gastritis
Multiple Gastric Carcinoids wang E, Sagel SS, Brunt EM RadioGraphics 2009;29:1206-1209
Types - Type I: most common and associated with hypergastrinemia, chronic atrophic gastritis with or without pernicious anemia (70-75%) - Type II: least common and associated with gastrin producing tumor of pancreas or small bowel and are seen with MEN-1 or Zollinger Ellison syndrome (5-10%) - Type III: not associated with hypergastrinemia and make up 13% of cases
Facts - Less than 1% of gastric tumors - 8.7% of GI carcinoid tumors - Three types including type II which is associated with MEN-I or Zollinger-Ellison syndrome - Can present as small <1cm polyps or diffuse gastric wall thickening
- Originate from Kulchitsky cells in the crypts of Lieberkuhn - Cytoplasm contains eosinophilic granules that have an affinity for solver stain (argenaffinomas) - < 35% of GI carcinoids are located in stomach - Most are in distal antrum
- Rare but recognized complication of prolonged severe hypergastrinemia - chronic atrophic gastritis gastrinoma - ? H2 blockers - Elevated gastrin levels can result in hyperplasia of ECL cells or carcinoid
- CT Findings - Submucosal mass or masses - Usually 1-4 cm - Can mimic gastric polyps - May have associated gastric fold thickening due to elevated gastrin levels.