A patient in our unit was recently diagnosed with pseudomyxoma peritonei (PMP). What is this?- T.C., FLA.

Lisa Janson, RN, replies: A rare condition with an unknown cause, PMP is a mucinous tumor of the appendix that may occur in otherwise healthy people. Eventually the tumor ruptures and cancerlike cells spread via peristalsis throughout the peritoneum. These cells produce mucus that collects in the abdomen as a jellylike fluid called mucin. The tumor generally doesn't spread beyond the abdominal and pelvic area.

Three types of PMP are recognized: disseminated peritoneal adenomucinosis, which is histologically benign; peritoneal mucinous adenocarcinoma, which is malignant and has a poor prognosis even with treatment; and a hybrid form. Most deaths from PMP are caused by advanced abdominal disease leading to intestinal obstruction. Because many signs and symptoms are nonspecific, PMP may be misdiagnosed (for example, as ovarian cancer) or not diagnosed at all. The most common symptoms are a gradually increasing abdominal girth and ascites. The growing tumor increases pressure on the gut, displaces the bowels, and prevents the patient from eating and breathing normally.

PMP tumors may be detected with exploratory laparoscopy. The tumors may also be revealed on computed tomography scans, but they're often misread due to practitioners' unfamiliarity with PMP.

Treatments for PMP include surgical debulking procedures to remove as much tumor as possible. However, the disease often recurs. Systemic chemotherapy may be used alone (although it's usually ineffective for the benign form of PMP) or with cytoreductive surgery (known as the Sugarbaker peritonectomy procedure). Cytoreductive surgery, which can produce remissions lasting more than 10 years, is the gold standard of treatment for PMP. The surgery involves very aggressive removal of all visible tumors and tumor destruction using electro-evaporation and argon beam coagulation (cytoreduction), followed by heated chemotherapy manually massaged directly into the peritoneal cavity. Heating the chemotherapy improves drug distribution and action as well as drug penetration into the tissue. Postoperatively, the patient may have 1 to 5 days more of abdominal chemotherapy via peritoneal dialysis. Candidates for this treatment option must be in very good general condition because the surgery can take 13 to 17 hours, complications are common, and recovery is lengthy.

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