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Pseudomyxoma Peritonei

Pseudomyxoma Peritonei

Overview:

  • A rare condition characterized by mucinous ascites and peritoneal implants, typically originating from a perforated mucinous tumor of the appendix.

Etiology:

  • Most often arises from a perforated mucinous tumor of the appendix.
  • Can be associated with mucinous tumors of the ovary, colon, and pancreas.

Pathophysiology:

  • Mucinous neoplasms categorized by:
    • The presence or absence of infiltrative invasion.
    • Cellular atypia into low-grade or high-grade.
  • Histology of appendiceal tumors is crucial for survival prediction.
    • Adenomucinosis has the best survival rate (75% at 5 years).
    • Peritoneal mucinous carcinomatosis has the worst (14% at 5 years).

Demographics:

  • Commonly occurs in individuals 40 to 50 years of age.
  • Similar frequency in men and women.

Clinical Presentation:

  • Often asymptomatic until the late stages.
  • Symptoms include abdominal pain, distension, and nonspecific complaints.
  • Physical examination may reveal hernia, ascites, abdominal distension, and sometimes a palpable mass.

Diagnosis:

  • CT scans of the chest, abdomen, and pelvis may show ascites, loculated fluid, and peritoneal-based tumor nodules.
  • Difficulties in achieving complete cytoreduction due to diffuse involvement of the small bowel or porta hepatis by the tumor.
  • Diagnosis is sometimes made at laparotomy.

Treatment:

  • Resection of as much tumor as possible (cytoreduction).
  • Hyperthermic intraperitoneal chemotherapy (HIPEC).
    • Common drugs used: Mitomycin C and Oxaliplatin.
  • Surgical management may include omentectomy, peritonectomy, and organ resection as needed.
  • Goal is to remove visible disease or, if this is not feasible, to leave no nodules larger than 2 mm in diameter.

Prognosis:

  • 5-year survival rates:
    • Low-grade tumors: up to 90% if complete cytoreduction.
    • High-grade tumors: up to 50% if complete cytoreduction.

Complications:

  • 30-day postoperative mortality at experienced centers: 2% to 3%.
  • 25% to 35% of patients will develop serious complications, most commonly:
    • Prolonged ileus.
    • Pulmonary complications.
    • Hemorrhage.
    • Intraabdominal infections.

Comprehensive Summary: Pseudomyxoma peritonei is a complex condition where early diagnosis is challenging due to the often asymptomatic nature of the disease. It manifests with mucinous ascites, primarily arising from the appendix, and can mimic features of other mucinous tumors. Histological grading of tumors is pivotal for prognosis, with adenomucinosis showing more favorable outcomes. Management involves aggressive surgical resection combined with HIPEC, targeting complete cytoreduction to improve survival outcomes. Despite aggressive treatment, the postoperative period can be complicated by significant morbidity. Awareness of demographic prevalence and potential complications is crucial for optimal patient management.