Pleural extension of mucinous tumor in patients with pseudomyxoma peritonei syndrome

Background: Pseudomyxoma peritonei syndrome is a rare disease arising from perforation of an adenoma of the appendix. The syndrome is characterized by progressive accumulation of mucinous fluid and tumor within the abdomen an d pelvis. Although this tumor is only superficially invasive and does not m etastasize, it is a fatal disease. Extra-abdominal spread of pseudomyxoma p eritonei is a rare occurrence, with few reports in the medical literature. This review focuses on pleural extension of mucinous tumor in patients with pseudomyxoma peritonei syndrome. Methods: From December 1983 to April 1999, all patients who underwent cytor eductive surgery for pseudomyxoma peritonei syndrome were assessed for pleu ral involvement at the time of the presentation or follow-up. Clinical info rmation on these patients, including chest computed tomographic scan, was r etrospectively reviewed. The mechanisms of extension of mucinous tumor from peritoneal cavity to pleural surface and the results of treatment were of special interest. Results: Twenty-three of 426 patients (5.4%) showed pleural extension of ps eudomyxoma peritonei syndrome. In four patients (17%), extension into the c hest occurred before cytoreductive surgery. In 18 patients, the pleural spa ce was entered during a subdiaphragmatic peritonectomy; and, in 12 patients , extension of disease from peritoneal to pleural space occurred. In six pa tients (26%), surgical interventions were required to excise tumor that had invaded the hemidiaphragm; and, in the six other patients (26%), there was a minor penetration during subphrenic peritonectomy, which was closed imme diately. Finally, in seven patients (30%), the mechanism of spread was unkn own. Twelve patients were treated for pleural thoracotomy. Eight patients h ad an attempt to completely eradicate pleural mucinous tumor, and five pati ents are currently disease free in the chest (22%); four of these five had intrapleural cytoreduction plus intrapleural chemotherapy. The median survi val for all 23 patients is 55 months. Conclusion: Pleural spread of pseudomyxoma peritonei syndrome may be a dire ct result of cytoreductive surgery and the subphrenic peritonectomy procedu re. In some patients, dissecting mucinous tumor may infiltrate through the diaphragm and result in pleural extension. Pleural extension of pseudomyxom a peritonei syndrome carries a poor prognosis. Intrapleural chemotherapy co mbined with cytoreductive surgery may be of considerable value in treatment and prevention of disease dissemination; it should be considered when pleu ral extension of mucinous tumor is feared or confirmed at the time of cytor eductive surgery.