Pseudomyxoma peritonei

Clinical picture

Pseudomyxoma peritonei (PMP) is a rare type of cancer that affects the peritoneum. This cancer affects around two people in one million and is mostly found in patients between 40 and 60 years old.

PMP originates as an adenoma, a benign growth that can develop into an adenocarcinoma, its malignant form. The most frequent place for PMP to develop is the appendix, but PMP has also been found in the ovaries, bladder and intestines. Basically, PMP causes cells inside the appendix to produce excessive amounts of mucus, potentially causing the appendix to rupture, which allows cancerous cells to spread throughout the abdomen and onto the peritoneum.

There are three types of PMP:

Disseminated peritoneal adenomucinosis (DPAM): This type causes only mucus to be formed. Mucous secreting cells do not show any deformation
Peritoneal mucinous carcinomatosis (PMCA): In this type, less than half of the tissue consists of mucus. Cells are deformed and grow faster
Peritoneal mucinous carcinomatosis with intermediate features (PMCA-I): this is an intermediate type of PMP

Symptoms

Due to the very slow development of PMP, patients do not experience any symptoms until the disease is in its later stages. Symptoms may include:

pain in the lower abdomen, sometimes with fever
hernia of navel or groin
intestinal complaints
inexplicable weight loss
difficulty in getting pregnant

The symptoms develop along the following stages:

Stage I: pain in the right lower abdomen
- This signals that the appendix has ruptured and tumorous cells are spreading through the abdominal cavity. The pain will dissipate after a few days
Stage II: no noticeable complaints
- The cancer produces mucus but does not cause pain or discomfort
Stage III: growing abdomen
- The build-up of mucus makes the abdomen grow larger. Typically, the weight of the patient will decrease while their waist size increases
Stage IV: hernia of navel or groin
- The continuing growth of the abdomen, due to mucus build-up, can cause a hernia
Stage V: growing fatigue and being out of breath
- The mucous build-up can make the abdomen grow to a size similar to a pregnancy, and displace the midriff
Stage VI: loss of appetite
- Because the stomach and intestines become compromised by the mucous build-up, there is less room for food, resulting in a loss of appetite. Significantly, the abdomen keeps growing despite of this

Cause

There is no known cause for PMP.

Diagnosis

Due to the rarity of PMP, the illness will most likely only be identified during its later stages by a specialist. Using ultrasounds, CT scans or MRI scans, PMP may be diagnosed, but keyhole surgery will, in most cases, provide a definitive diagnosis.

Treatment

The choice of treatment for PMP patients is a combination of surgery and chemotherapy. The surgeon will try to remove as many tumorous growths from the abdomen as possible, following it up with chemotherapy in order to kill off any remaining cancer cells. The efficacy of the chemotherapy can be improved by heating the medication before administration. This procedure is known as HIPEC: hyperthermic intraperitoneal chemotherapy. If curing the patient is no longer a viable option, HIPEC can also be offered in a palliative setting.