appendiceal carcinoid

Appendiceal carcinoids are rare overall but represent the most common tumor of the appendix. The appendix is also one of the most common (but not the most common) locations for gastrointestinal carcinoid tumors.

Clinical presentation

Appendiceal carcinoids can present as the obstructive cause of acute appendicitis or less commonly a mucocele. Often they are incidental findings .

Pathology

Appendiceal carcinoids are neuroendocrine tumors that classically arise at the appendiceal tip from subepithelial neuroendocrine cells .

Histology

Two types are described :

  • classic type
  • Goblet cell carcinoid
    • considered a distinct tumor, separate from classic neuroendocrine tumor, with its own evolving classification based on degree of differentiation

Radiographic features

CT
  • small (usually <1 cm), round masses or diffuse appendiceal thickening
  • most commonly at the appendiceal tip (75%)

Treatment and prognosis

Appendiceal carcinoids have a more benign course than other gastrointestinal carcinoids, rarely metastasizing, with a 5-year survival rate of >90% .

Metastases, when they do occur are to regional nodes, and rarely the liver .

Differential diagnosis

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