Pseudomyxoma peritonei is a rare cancer which usually originates in the appendix, although it has been found to develop in other abdominal organs, such as the ovaries and the bladder. Unlike other cancers, pseudomyxoma peritonei does not spread to distant organs, as the cells do not travel through the blood or the lymph nodes. These cancer cells instead stay inside the peritoneal cavity, where they produce mucus which accumulates over time.
The peritoneal cavity is a space in the center of the body containing organs including the stomach, intestines, and liver. This cavity usually secretes approximately 1.6 ounces (about 50 ml) of mucus daily, which acts as a lubricant inside the abdomen. Pseudomyxoma peritonei is characterized by unusually large amounts of mucus produced the peritoneal cavity.
When pseudomyxoma peritonei grows inside the appendix, it can cause the appendix to burst and cancer cells to spread in the abdominal cavity. These cancer cells do not commonly adhere to other organs, but instead mix with the fluid inside the abdomen, continually producing mucus. The increasing volume of mucus inside the abdomen will eventually compress vital organs in the gastrointestinal tract. Symptoms of pseudomyxoma peritonei include swelling of the abdomen, changes in bowel movements, constipation or diarrhea, abdominal pain, shortness of breath, and loss of appetite.
Men with pseudomyxoma peritonei may develop an inguinal hernia. An inguinal hernia is a defect in the abdominal muscle that causes fats or portions of the small intestines to protrude through the lower abdominal wall; it usually presents as a bulge in the groin. In women, the cancer is frequently felt by physicians during a pelvic examination as a mass in the ovary. Other manifestations of the disease are the appendicitis-like symptoms felt by patients. These include pain in the right lower side of the abdomen, vomiting, nausea, loss of appetite, and fever.
Surgery is usually needed to remove the tumor cells in the abdomen. Depending on how widely the cancer appears to have spread, the spleen, gall bladder, and portions of the intestines may also be removed; in women, the uterus and the ovaries may be removed as well. Pseudomyxoma peritonei can recur if not all cancer cells are removed during the operation, so chemotherapy drugs are often placed in the abdomen after surgery to treat any remaining cancer cells. This procedure is not suitable for all patients, however, as it is a long and complex process, and serious complications can arise.