Summary
Appendiceal cancer is a rare malignancy of the appendix that is most commonly discovered incidentally on cross-sectional imaging or after routine appendectomy. There are several distinct histological subtypes, including appendiceal neuroendocrine tumors, mucinous adenocarcinoma, colonic-type adenocarcinoma, and the more aggressive goblet cell and signet ring adenocarcinomas. While many patients are asymptomatic, clinical presentation ranges from carcinoid syndrome to pseudomyxoma peritonei from mucinous tumors with peritoneal spread. Diagnosis is confirmed by histopathology, and further workup involves cross-sectional CT or MRI imaging, colonoscopy, and serum tumor markers (e.g., CEA, CA 19-9, and CA-125). Management is guided by a multidisciplinary team and depends on the tumor's histology and stage. Localized disease is typically treated surgically with an appendectomy or a right hemicolectomy, sometimes with adjuvant chemotherapy. For disease with peritoneal involvement, treatment often involves a combination of systemic chemotherapy and cytoreductive surgery.
Diagnostic approach
Appendiceal cancer is most commonly detected incidentally on diagnostic imaging or after routine appendectomy. [1]
Laboratory studies
- Serum tumor markers (e.g., CEA, CA 19-9, CA-125) [1]
- CRP [1]
- Consider molecular and genetic testing (e.g., comprehensive tumor profiling, circulating tumor DNA). [1]
Imaging
- Cross-sectional imaging of the chest, abdomen, and pelvis with CT or MRI for staging [2]
- Consider neuroendocrine tumor-specific imaging (e.g., Gallium–68 DOTATATE PET/CT) in select cases. [2]
Diagnostic procedures
- Colonoscopy to rule out synchronous colorectal lesions in patients with appendiceal neuroendocrine tumors [2]
- Consider surgical exploration (e.g., diagnostic laparoscopy) with biopsy for definitive diagnosis if the tumor is identified on imaging. [1]
Histopathology [2][3]
- Confirm diagnosis via histologic analysis of the surgical specimen (i.e., from appendectomy or biopsy).
- Ensure review of pathology specimens by a gastrointestinal pathologist.
Appendiceal mucinous adenocarcinoma
Definition
- A subtype of appendiceal adenocarcinoma characterized by infiltrative growth of invasive glands with > 50% of the lesion composed of extracellular mucin [2]
Epidemiology
- Most common type of epithelial appendiceal malignancy, accounting for 35–40% of cases [1]
Clinical features
- Frequently asymptomatic [1]
- Patients with peritoneal spread may present with mucinous ascites (e.g., pseudomyxoma peritonei). [3]
Management
- Localized disease: appendectomy alone or conservative resection (e.g., appendiceal cuff resection or partial cecectomy) [1][2]
- Metastatic disease (e.g., peritoneal involvement): cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy [3]
Appendiceal neuroendocrine tumor
Definition
- A type of nonepithelial neoplasm of the appendix, most often identified incidentally after routine appendectomy [2]
Epidemiology
- 1%–2% annual prevalence in appendectomy specimens in the US [2]
- ∼ 20% of all appendiceal tumors [1]
Clinical features
- Frequently asymptomatic [2]
- Can manifest with carcinoid syndrome, which may indicate metastatic disease or a synchronous colonic neoplasm [2]
Management
- Colonoscopy: before surgical resection to assess for concurrent colorectal neoplasm [2]
- Appendectomy: < 1 cm tumor with favorable histologic features (can be curative) [2]
- Right hemicolectomy
Appendiceal colonic-type adenocarcinoma
Definition
- A subtype of appendiceal adenocarcinoma characterized by infiltrative growth and histologic features that resemble colorectal adenocarcinoma [2]
Epidemiology
- 7–27% of all appendiceal tumors [1]
Management
-
Localized disease
- Right hemicolectomy with lymphadenectomy [1][2]
- Adjuvant systemic chemotherapy for advanced disease (e.g., lymph node involvement) [1]
-
Metastatic disease (with peritoneal involvement)
- Systemic chemotherapy to assess disease response before surgical planning [3]
- Surgical options include: [2][3]
Goblet cell adenocarcinoma
Definition
- A rare and aggressive appendiceal neoplasm characterized histologically by a mix of neuroendocrine and epithelial cells [2][3]
Epidemiology
- ∼ 20% of all appendiceal tumors [1]
Management
- Localized disease: right hemicolectomy with lymphadenectomy [2][3]
-
Metastatic disease (e.g., peritoneal involvement)
- Systemic chemotherapy to assess disease response before surgical planning [3]
- Surgical options include: [2][3]
Appendiceal signet ring adenocarcinoma
Definition
- An aggressive neoplasm in which > 50% of the tumor is composed of signet ring cells [2]
Epidemiology
- < 10% of all appendiceal tumors [1]
Management
- Localized disease: right hemicolectomy with lymphadenectomy [1][2]
-
Metastatic disease (e.g., peritoneal involvement)
- Systemic chemotherapy to assess disease response before surgical planning [1]
- Cytoreductive surgery for select patients [2]