Pseudomyxoma Peritonei
Definition
- A clinical condition characterized by accumulation of mucin in the abdominal or pelvic cavity
Diagnostic Criteria
- A clinical condition, not a pathologic diagnosis
- Extensive secretion and accumulation of mucin in the peritoneal space
- Usually produces abdominal distension
- Characterized by re-accumulation after debulking
- Ultimately leads to intestinal obstruction
- No metastatic spread to nodes or organ parenchyma other than ovary
- Pleural involvement rare
- Due to communications across the diaphragm
- Approximately 50% 5 year survival with aggressive, repeated debulking
- Disease progresses inexorably to 20% 10 year survival
- Contrasts with very short survival for carcinomatosis
- Histopathologic findings usually correspond to appendiceal mucinous neoplasm with high risk of recurrence
- Paucicellular mucin implants
- Degree of cellularity may be prognostic
- Cytologic atypia should be low grade
- Cytologic atypia does not change with time or recurrences
- High grade cytology is an indication of peritoneal carcinomatosis rather than pseudomyxoma
- Epithelial elements simple or focally proliferative
- Complex, cribriform architecture indicative of carcinomatosis
- Implants should be non-invasive
- Invasion indicates carcinomatosis
- Vast majority of cases of pseudomyxoma peritonei are associated with appendiceal mucinous neoplasms with high risk of recurrence
- Occasional cases associated with appendiceal mucinous neoplasms with low risk of recurrence
- Rare reports of association with neoplasms of other sites in most cases probably represent peritoneal carcinomatosis or failure to examine completely the appendix
- Rarely associated with mucinous neoplasms arising in teratomas
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 10/7/10