Everything you need to know about Computed Tomography (CT)

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Stomach: Carcinoid Tumors Imaging Pearls - Learning Modules | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Stomach ❯ Carcinoid Tumors
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  • Benign gastric tumors
    • Although these lesions demonstrate different histologic findings, the overlap of radiologic findings in many gastric tumors makes differentiation difficult.
    • Clinical manifestations also overlap and can vary from severe abdominal pain and acute abdomen to vague signs such as weight loss and anemia.
    • some gastric tumors cause diagnostic confusion, which may result in unnecessary surgery or inappropriate follow-up.
    • some unusual gastric tumors have characteristic radiologic features that may suggest a specific diagnosis.
  • Lipoma
    • Benign submucosal tumor composed of mature adipose tissue.
    • 2%–3% of benign gastric tumors
    • Usually detected incidentally.
    • Large lipomas may have ulcerations as a result of pressure necrosis of the overlying mucosa and cause gastrointestinal bleeding.
    • Can cause intussusception or bowel obstruction.
    • Tend to occur as solitary lesions
    • Most frequently in the gastric antrum
  • Gastric Duplications
    • 7% of gastrointestinal tract duplications.
    • Most are noncommunicating, spheric or ovoid closed cysts, and the most common site is the greater curvature
    • The mucosal lining is usually gastric, but pseudostratified respiratory epithelium and pancreatic tissue have been found
    • The clinical picture depends on their size and location as well as the presence of communication with the rest of the alimentary tract.
    • Most duplications are discovered in infants. Vomiting and abdominal pain are the predominant clinical findings, although patients are frequently asymptomatic.
    • US and CT show a well-defined cystic mass lying close to the greater curvature of the stomach. The presence of an echogenic inner rim and hypoechoic outer muscle layers is highly suggestive of a duplication
  • Leiomyoma
    • Mesenchymal tumors of the gastrointestinal tract are usually incidentally discovered as a firm, protruding submucosal lesion during upper gastrointestinal examinations for unrelated conditions
    • The larger tumors may occasionally cause bleeding
    • Pathologically, most of these tumors are composed of spindle cells and display smooth muscle differentiation.
    • Gastric mesenchymal tumors are classified immunohistochemically as leiomyomas or GISTs
    • In particular, the leiomyomas are defined as being desmin positive and c-kit (CD117) negative tumors and the GISTs are defined as being c-kit positive tumors.
  • Schwannoma
    • Neurogenic tumors of the stomach are rare
    • Approximately 4% of all benign gastric tumors
    • The majority of these tumors are schwannomas
    • Included in the smaller group of gastrointestinal mesenchymal tumors, which contains relatively well-differentiated tumors that are identical to those arising from the somatic soft tissue
    • Usually appear as discrete submucosal masses that are indistinguishable from other mesenchymal tumors
    • As they outgrow their blood supply, these lesions may undergo central necrosis and ulceration.
    • Schwannomas and gastrointestinal stromal tumors that show differentiation toward neural elements are histologically different tumors, although the relation between them is not clear
  • Glomus Tumor
    • The most common benign vascular tumors of the stomach
    • Typically originate from glomus bodies, which are specialized arteriovenous communications that regulate skin temperature.
    • Usually occur in the gastric antrum
    • Typically single tumors
    • The majority of affected patients are asymptomatic
    larger lesions are likely to be ulcerated and may cause upper gastrointestinal bleeding.
    • At radiology, these tumors appear as smooth submucosal masses with or without ulceration
    • Occasionally, may contain tiny flecks of calcification
    • Enhance strongly on early-phase
  • Heterotopic pancreas
    • The incidence in autopsies ranges 0.5%-13.7
    • more common at the age of 30-50 years with a male predominance
    • The usual location is in the stomach in 25%-38% of the cases, duodenum in 17%-36%, jejunum in 15%-21.7% and rare in the esophagus, gallbladder, common bile duct, spleen, mesentery, mediastinum and fallopian tubes.
    • Gastric lesions are discovered in the antrum in 85%-95%, either on the posterior or anterior wall, being more common along the greater curvature.
    • CT usually non specific may demonstrate the lesion which enhances similarly with the normal pancreatic tissue
  • “Gastric lipoma is a rare lesion, ac- counting for only 5% of gastrointestinal tract lipomas and fewer than 1% of all gastric tumors. Most gastric lipomas are small asymptomatic lesions that are detected as incidental findings at autopsy. The tumor is composed of well- differentiated adipose tissue surrounded by a fibrous capsule. Most gastric lipomas are found in the submucosa, and most are located in the pyloric antrum.”


    Imaging Characteristics of Gastric Lipomas in 16 Adult and Pediatric Patients 
Thompson WM et al. 
AJR 2003;181:981–985
  • “When the tumors are large (> 3–4 cm), the most common clinical presentation is upper gastrointestinal hemorrhage, either chronic or acute, caused by ulceration of the neoplasm. Abdominal pain and ob- structive symptoms are also common, especially if there is endoluminal growth that could cause intussusception.”


    Imaging Characteristics of Gastric Lipomas in 16 Adult and Pediatric Patients 
Thompson WM et al. 
AJR 2003;181:981–985
  • “Gastric lipomas larger than 3 cm are usually symptomatic. The most common findings pre-viously reported in the literature —obstruction and gastrointestinal bleeding—were found in our series. In our 16 patients, abdominal pain was the most common symptom (eight patients, 50%), with gastrointestinal bleeding present in six patients (38%). In two patients (13%) with no abdominal symptoms, 
the gastric lipomas were discovered incidentally on imaging studies performed for reasons other than upper gastrointestinal symptoms, an occurrence that is not rare in patients with gastric lipomas.”

    Imaging Characteristics of Gastric Lipomas in 16 Adult and Pediatric Patients 
Thompson WM et al. 
AJR 2003;181:981–985
  • “In conclusion, our review of data for 16 patients with proven gastric lipomas revealed two significant findings. First, on upper gastrointestinal examinations, lipomas have the appearance of any submucosal tumor; they are indistinguishable from gastrointestinal stroma tumors or lymphoma. Second, CT findings are specific for the diagnosis of gastric lipoma. CT should be used to characterize large submucosal masses before endoscopic biopsy is performed.”

    Imaging Characteristics of Gastric Lipomas in 16 Adult and Pediatric Patients 
Thompson WM et al. 
AJR 2003;181:981–985
  • Carcinoid Tumor: Facts
    - Gastric carcinoids are rare and make up less than 2% of gastric neoplasms
    - GI carcinoids most common in small bowel, followed by the rectum, appendix and stomach
    - Majority of gastric carcinoids have atrophic metaplastic autoimmune gastritis with or without pernicious anemia
  • Carcinoid Tumor: Facts
    - 5-10% of gastric carcinoids are caused by hypergastrinemia from a gastrin producing tumor in association with MEN type 1.
    - Approximately 30% of MEN1 patients have a gastric carcinoid tumor
    - May be solitary or multiple gastric lesions
    - Usually hypervascular on CT
  • Carcinoid Tumor: Facts
    - Patients with type 2 gastric carcinoids have symptoms of ZE syndrome, with abdominal pain or bleeding from multiple ulcers, diarrhea and elevated serum gastrin levels
    “ 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
  • “ 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
All images on this site are © 2017 Elliot K. Fishman, MD.