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Carcinoid Tumors

“ 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
Gastric Carcinoid:

Low grade malignancies

Can metastasize

Treatment
- Treatment of hypergastrinemia
- Endoscopic excision
- Surgical resection
- Endoscopic surveillance

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
gastrinoma
? H2 blockers
Multiple Gastric Tumors: Differential Diagnosis
- Carcinoid tumor

- Hyperplastic polyps (75% of cases)

- Adenomatous polyps Peutz-Jeghers syndrome
- Multiple hamartoma syndrome (Cowden disease)

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
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 gastrinoma
- ? H2 blockers
- Elevated gastrin levels can result in hyperplasia of ECL cells or carcinoid
Gastric 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.
Gastric Carcinoid

- Low grade malignancies
- Can metastasize
- Treatment
- Treatment of hypergastrinemia
- Endoscopic excision
- Surgical resection
- Endoscopic surveillance