Pseudomyxoma

Pseudomyxoma, commonly referred to as pseudomyxoma peritonei (PMP), is a rare clinical syndrome characterized by the accumulation of mucinous, gelatinous material within the peritoneal cavity. It most often originates from mucin-producing neoplasms of the appendix and less commonly from ovarian or other abdominal tumors. The condition occurs when tumor cells disseminate within the peritoneum and continue to secrete mucin.

Etiology and pathology: The disease typically arises from an appendiceal mucinous neoplasm; malignant or low-grade mucinous neoplasms can seed the peritoneum, producing copious mucin without a discrete mass. The peritoneal surfaces become coated with mucin and tumor implants, leading to progressive abdominal distension and impaired organ function.

Clinical features: Patients present with increasing abdominal girth and fullness, abdominal discomfort, and sometimes changes in bowel habit. The abdomen may have a gelatinous appearance during surgery, and patients may describe a sensation of a “jelly belly” due to the mucinous ascites.

Diagnosis: Computed tomography and magnetic resonance imaging help define mucinous ascites and peritoneal involvement; ultrasound can be useful. Diagnosis is confirmed by histopathology, often from surgically obtained specimens. Histologic grade (low vs high) and the extent of peritoneal disease guide prognosis and treatment.

Treatment and prognosis: The main therapy is cytoreductive surgery to remove tumor implants, combined with intraperitoneal chemotherapy such as HIPEC or EPIC. In unresectable or recurrent disease, systemic chemotherapy or palliative care may be used. Prognosis depends on histologic grade and completeness of tumor removal; long-term survival is possible for selected patients, but recurrence is common.