Pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP), also known as 'jelly belly,' is a rare clinical condition characterized by the progressive accumulation of mucinous (gelatinous) ascites within the peritoneal cavity — the space that surrounds the abdominal organs. In the vast majority of cases, PMP originates from a ruptured mucinous neoplasm of the appendix (such as a low-grade appendiceal mucinous neoplasm, or LAMN), though rarely it may arise from other sites including the ovary, colon, or urachus. The mucinous tumor cells spread along peritoneal surfaces, producing large volumes of mucin that progressively fill the abdomen. This process is sometimes referred to as 'redistribution phenomenon,' as mucin tends to accumulate in dependent areas and along the greater omentum. Key symptoms include progressive abdominal distension, increasing abdominal girth, abdominal or pelvic pain, bloating, changes in bowel habits, and sometimes new-onset hernias. Many patients are diagnosed incidentally during surgery for suspected appendicitis or during imaging for unrelated conditions. As the disease progresses, the accumulating mucin can compress abdominal organs, leading to bowel obstruction, nutritional compromise, and significant morbidity. PMP is classified histopathologically into low-grade (disseminated peritoneal adenomucinosis) and high-grade (peritoneal mucinous carcinomatosis) subtypes, with prognosis varying significantly between these categories. The current standard of care for PMP is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). This aggressive approach involves surgically removing all visible tumor and mucin from the peritoneal cavity, followed by bathing the abdomen in heated chemotherapy (typically mitomycin C or oxaliplatin). When performed at experienced centers, this treatment can achieve long-term survival rates exceeding 70–80% at 10 years for low-grade disease. Systemic chemotherapy may be used for high-grade disease or when surgery is not feasible. Lifelong surveillance with tumor markers (CEA, CA 19-9, CA-125) and imaging is recommended due to the risk of recurrence.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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