Appendix Cancer

What it is

Overview

Appendix cancers are rare tumors of the appendix that include several distinct histologic types: appendiceal carcinoid (NET), mucinous adenocarcinoma, goblet cell carcinoid, and signet ring cell adenocarcinoma. They are often asymptomatic and discovered incidentally during appendectomy for appendicitis. Advanced cases can present with pseudomyxoma peritonei — diffuse spread of mucin through the abdominal cavity.

Biology

How It Develops

Appendiceal neoplasms arise from different cell types within the appendix. Carcinoid tumors originate from neuroendocrine cells; mucinous adenocarcinomas arise from glandular epithelium and can rupture, seeding the peritoneum with mucin-producing cells. The KRAS, GNAS, and SMAD4 mutations are common in mucinous adenocarcinomas.

Warning signs

Symptoms

• —Often asymptomatic (found at appendectomy)
• —Abdominal pain or acute appendicitis presentation
• —Increasing abdominal girth (from pseudomyxoma peritonei)
• —Bloating and bowel changes (advanced disease)

Detection

Diagnosis Methods

• —CT scan of abdomen and pelvis
• —MRI for peritoneal extent
• —Pathological examination of appendix after surgery
• —Tumor markers: CEA, CA-125, CA 19-9

Medical care

Treatment Options

• —Appendectomy or right hemicolectomy (for adenocarcinoma)
• —Cytoreductive surgery (CRS) with heated intraperitoneal chemotherapy (HIPEC) for peritoneal disease
• —Systemic chemotherapy (FOLFOX, FOLFIRI)
• —Somatostatin analogs for carcinoid/NET tumors

Data

Statistics

Prevention

Risk Factors

• —No well-established risk factors
• —Some association with prior appendiceal inflammation

Further reading

Resources