Pseudomyxoma peritonei

Pseudomyxoma peritonei (also known as PMP, or sometimes colloquially as "jelly belly") is an uncommon tumor known for its production of mucus in the abdominal cavity.^[1] The tumor is not harmful by itself, but the mucus has no place to go inside the abdominal cavity. If left untreated, it will eventually build up to the point where it compresses vital structures: the colon, the liver, kidneys, etc.

Unlike most cancers, PMP does not spread through the lymphatic system or through the bloodstream. PMP is most commonly associated with cancer of the appendix; mucinous tumors of the ovary have also been implicated.

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Clinical

PMP may be diagnosed with a range of conditions. While the majority of PMP cases are associated with appendiceal carcinomas,^[2] other conditions may also be found, including disseminated peritoneal adenomucinosis (DPAM), peritoneal carcinomas, several mucinous cancers (mucinous adenocarcinoma, mucinous cystadenoma, and mucinous cystadenocarcinoma), as well as other disease states.^[3] Symptoms may include abdominal or pelvic pain and/or bloating, distension, digestive disorders, weight changes, increased girth and infertility. Diagnosis is confirmed through pathology. Diagnostic tests may include CT scans, and the evaluation of tumor markers.

PMP is commonly discovered during surgery for other conditions, i.e., hernia repair, following which an experienced pathologist can confirm the diagnosis. Due to the rarity of this disease, it is important to obtain an accurate diagnosis so that appropriate treatment may be obtained.

Treatment

Treatment for PMP is variable, both due to its rarity and to its frequently slow-growing nature. Treatment ranges from watchful waiting to debulking and cytoreductive surgery.^[4]

Surgical

Most commonly, treatment for PMP involves surgery performed by specific specialists trained in treating this disease.

When appropriate, surgery may include intraperitoneal hyperthermic chemotherapy, or post operative systemic chemotherapy.

In situations where surgery is not required immediately, patients can be monitored via CT scans, tumor marker laboratory tests, and physical symptoms, to determined when, and if, surgery is warranted.

Although some surgical procedures may be rather extensive, patients can and do recover from surgery, and the majority of these patients can and do live productive lives.

In debulking, the surgeon attempts to remove as much tumor as possible, while cytoreductive surgery involves surgical removal of the peritoneum and any adjacent organs which appear to have tumor seeding. Since the mucus tends to pool at the bottom of the abdominal cavity, it is common to remove the ovaries, fallopian tubes, uterus, and parts of the large intestine. Depending upon the spread of the tumor, other organs might be removed, including but not limited to the gallbladder, spleen, and all or portions of the small intestine and/or stomach. For organs that cannot be removed safely (like the liver), the surgeon strips off the tumor from the surface. ^[5]

Drug treatments

Chemotherapy is infused directly into the abdominal cavity to kill remaining cancerous cells. The drugs may be manually applied to the cavity for an hour or two as the last step in the surgery, or ports are installed to allow circulation and/or drainage of the chemicals for one to five days after surgery. Cancer cells reproduce quickly on scar tissue, and there is lots of scar tissue after surgery. Even with aggressive, heated chemotherapy treatment PMP recurrence is common and further surgeries are frequently needed. Patients often require frequent CT scans for a period of time to spot any tumor regrowth.

Oral and intravenous chemotherapy has become more commonly used during the past five years. In cases in patients have experienced stability in tumor growth through treatment with various systemic chemotherapies.

Additionally recent (2003) publications linking the MUC2 enzyme overexpression to Pseudomyxoma cell reproduction has launched research efforts into additional drug treatments.

References