What is the management plan for a patient with a mucocoele of the appendix?

Management of Appendiceal Mucocoele

Surgical resection with careful, intact removal is the definitive treatment for appendiceal mucocoele, with the extent of surgery determined by histologic type and size—simple appendectomy for benign lesions (retention cysts, mucosal hyperplasia, cystadenoma) and right hemicolectomy for cystadenocarcinoma—while avoiding rupture at all costs to prevent pseudomyxoma peritonei. 1, 2, 3

Preoperative Diagnosis and Imaging

• Preoperative diagnosis is challenging as mucocoeles present with nonspecific symptoms ranging from asymptomatic incidental findings to clinical features mimicking acute appendicitis 2, 4
• CT scan and ultrasound are essential for identifying the characteristic cystic, tubular structure extending from the cecum, which helps distinguish mucocoele from simple appendicitis and allows surgical planning 5, 4, 3
• Colonoscopy must be performed in all patients with appendiceal mucocoele, as there is a significant association with synchronous colon cancer (reported in up to 40% of cases) 5

Surgical Approach Based on Histology

For Benign Mucocoeles (Retention Cysts, Mucosal Hyperplasia, Cystadenoma):

• Simple appendectomy is adequate when the mucocoele is caused by benign pathology 1, 3
• Laparoscopic approach may be considered but only if the surgeon can ensure intact removal without rupture; open surgery is safer when there is any concern about maintaining mucocoele integrity 2, 4
• The appendix must be removed intact without rupture to prevent spillage of mucin and epithelial cells into the peritoneal cavity 1, 2

For Malignant Mucocoeles (Cystadenocarcinoma):

• Right hemicolectomy is mandatory for cystadenocarcinoma to achieve adequate oncologic margins 1, 3
• Intraoperative frozen section should be obtained if there is any suspicion of malignancy based on size (>2 cm), appearance, or imaging characteristics 4

Critical Intraoperative Considerations

• Gentle handling is paramount—the mucocoele must not be ruptured during mobilization or removal, as this converts a curable condition into potentially fatal pseudomyxoma peritonei 1, 2
• If rupture occurs intraoperatively, copious peritoneal lavage should be performed immediately, though this does not eliminate the risk of pseudomyxoma peritonei 1
• Inspect the entire peritoneal cavity for evidence of mucin or gelatinous material suggesting pre-existing rupture or pseudomyxoma peritonei 1, 4

Management of Pseudomyxoma Peritonei

• If pseudomyxoma peritonei is identified (mucinous ascites with peritoneal implants), the patient requires cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) at a specialized center 1
• Do not attempt complete debulking if pseudomyxoma is discovered unexpectedly during initial surgery; close and refer to a specialized peritoneal surface malignancy center 1

Postoperative Surveillance

• Long-term follow-up with serial imaging (CT or MRI) is required for all patients, particularly those with cystadenoma or cystadenocarcinoma, to detect recurrence or development of pseudomyxoma peritonei 4
• Colonoscopy surveillance should follow standard guidelines for patients with synchronous colon pathology 5

Common Pitfalls to Avoid

• Never perform laparoscopic appendectomy if a mucocoele is suspected preoperatively or discovered intraoperatively, as the risk of rupture is substantially higher with laparoscopic manipulation 2, 4
• Do not mistake mucocoele for simple appendicitis and proceed with routine appendectomy without careful inspection—the firm, cystic, enlarged appendix should immediately alert the surgeon to alter technique 2, 4
• Avoid biopsy or needle aspiration of suspected mucocoeles, as this can cause rupture and seeding 1
• Do not overlook the association with colon cancer—failure to perform colonoscopy misses synchronous malignancies in a significant proportion of patients 5

Prognosis

• Excellent prognosis for benign mucocoeles when removed intact, with essentially no recurrence risk 4, 3
• Poor prognosis if pseudomyxoma peritonei develops, with this condition being potentially fatal despite aggressive treatment 1, 4
• Cystadenocarcinoma requires oncologic follow-up similar to other appendiceal malignancies, with 5-year survival dependent on stage and completeness of resection 4