Pleural extension of mucinous tumor in patients with pseudomyxoma peritonei syndrome

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 and pelvis. Although this tumor is only superficially invasive and does not metastasize, it is a fatal disease. Extra-abdominal spread of pseudomyxoma peritonei 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.

From December 1983 to April 1999, all patients who underwent cytoreductive surgery for pseudomyxoma peritonei syndrome were assessed for pleural involvement at the time of the presentation or follow-up. Clinical information on these patients, including chest computed tomographic scan, was retrospectively reviewed. The mechanisms of extension of mucinous tumor from peritoneal cavity to pleural surface and the results of treatment were of special interest.

Twenty-three of 426 patients (5.4%) showed pleural extension of pseudomyxoma peritonei syndrome. In four patients (17%), extension into the chest occurred before cytoreductive surgery. In 18 patients, the pleural space was entered during a subdiaphragmatic peritonectomy; and, in 12 patients, extension of disease from peritoneal to pleural space occurred. In six patients (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 immediately. Finally, in seven patients (30%), the mechanism of spread was unknown. Twelve patients were treated for pleural thoracotomy. Eight patients had an attempt to completely eradicate pleural mucinous tumor, and five patients are currently disease free in the chest (22%); four of these five had intrapleural cytoreduction plus intrapleural chemotherapy. The median survival for all 23 patients is 55 months.

Pleural spread of pseudomyxoma peritonei syndrome may be a direct result of cytoreductive surgery and the subphrenic peritonectomy procedure. In some patients, dissecting mucinous tumor may infiltrate through the diaphragm and result in pleural extension. Pleural extension of pseudomyxoma peritonei syndrome carries a poor prognosis. Intrapleural chemotherapy combined with cytoreductive surgery may be of considerable value in treatment and prevention of disease dissemination; it should be considered when pleural extension of mucinous tumor is feared or confirmed at the time of cytoreductive surgery.