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  • • Most diagnosed during appendectomy for acute appendicitis

    • Some discovered as incidental findings during other abdominal procedures

    • Mucin secretion from peritoneal cystadenocarcinoma implants is the cause of pseudomyxoma peritonei




  • • 4.6% incidence of benign tumors in appendectomy specimens

    • 1.4% incidence of malignant tumors in appendectomy specimens

    • Benign lesions include small carcinoid and mucocele

    • Malignant tumors include carcinoid, mucinous cystadenocarcinoma, and adenocarcinoma

    • Appendix most common location of GI carcinoids

    • Most carcinoids are < 2 cm and are located at the tip of the appendix

    • Carcinoids > 1.5 cm may exhibit malignant behavior

    • Widespread metastases are present in 10-50% of patients with appendiceal adenocarcinoma


Symptoms and Signs


  • • Diagnosis virtually never made preoperatively

    • Clinical presentation in most patients is either acute appendicitis or lack of symptoms

    • Clinical presentation in small portion of patients is the carcinoid syndrome or evidence of widespread metastases

    • Rarely is a palpable mass present

    • Ascites may be present in patients with a ruptured or metastatic mucin-secreting tumor


Laboratory Findings


  • • Findings consistent with acute appendicitis

    • Patients with carcinoid syndrome may have elevations of 5-hydroxyindoleacetic acid (HIAA)


Imaging Findings


  • • Most common radiographic findings are those consistent with acute appendicitis (enlarged appendix with peri-appendiceal fat stranding on CT)

    • Up to 15% of patients have formed peri-appendiceal abscesses

    • Tumors > 1-2 cm may be detected as an appendiceal mass on CT scan, although tumors usually obscured by surrounding bowel


  • • Acute appendicitis

    • Appendiceal abscess

    • Carcinoid

    • Mucinous cystadenoma

    • Mucinous cystadenocarcinoma

    • Adenocarcinoma

    • Adenocarcinoid

    • Lymphoma

    • Metastasis to the appendix


Rule Out


  • • Synchronous carcinoid neoplasms

    • Metastatic disease


  • • Most diagnoses depend on pathologic evaluation of the appendiceal specimen

    • Abdominal/pelvic CT scan to evaluate for metastatic disease

    • Somatostatin receptor scintigraphy can be helpful with carcinoid tumors

    • Up to 35% of patients with adenocarcinoma have a second GI malignancy


When to Refer


  • • Patients with evidence of lymph node involvement or metastatic disease


  • • Following recovery from initial surgical procedure, further resection should be considered






  • • Carcinoids < 2 cm are treated with appendectomy alone

    • Carcinoids > 2 cm or with mucinous elements, or invasion of the mesoappendix or cecum, should have right hemicolectomy

    • All (nonmetastatic) adenocarcinoma should be treated with right hemicolectomy

    • Localized hepatic masses should be resected

    • Debulking of cystadenocarcinoma mucin-secreting peritoneal implants provides symptomatic relief




  • • Unresectable metastatic disease




  • • Very good for benign lesions and small carcinoids

    • Adenocarcinoma 5-year survival 60% after right hemicolectomy

    • Prolonged survival with metastatic carcinoid and mucinous cystadenocarcinoma is common



Chiou YY et al: Rare benign and ...

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