Cleveland Clinic Journal of MedicineMucinous Ascites: Pseudomyxoma Peritonei

Pseudomyxoma Peritonei: Pancreaticobiliary Adenocarcinoma as a Rare Origin

In a recent clinical case, a 59-year-old male presented with progressive abdominal distention due to mucinous ascites, leading to a diagnosis of pseudomyxoma peritonei (PMP), a rare clinicopathologic syndrome. The importance of recognizing unusual ascitic characteristics to guide differential diagnosis and subsequent management is reinforced, illustrating the need for detailed cytological and imaging assessments in establishing the etiology.

Key Points:

• A 59-year-old patient with hypertension experienced two months of progressive abdominal distention, pain, and fatigue, leading to hospitalization for large-volume ascites as revealed by point-of-care ultrasonography.
• Ascitic fluid was notably viscous and jelly-like, prompting further evaluation beyond typical causes of ascites, leading to the consideration of pseudomyxoma peritonei (PMP).
• Laboratory tests showed slightly elevated cancer antigen (CA 19-9) levels, while other parameters remained within normal limits, ruling out common hepatic and renal causes of ascites.
• Fluid cytology confirmed the presence of mucin and atypical malignant cells, reinforcing suspicions of PMP.
• MRI and CT scans indicated peritoneal carcinomatosis, potentially linked to a pancreaticobiliary adenocarcinoma, despite a normal appendix and lack of other primary tumor sources.
• PMP typically arises from low-grade appendiceal mucinous neoplasms but can occasionally originate from other intra-abdominal sources like the pancreas, as suggested by the patient’s pancreatic duct dilation and greater omentum thickening.
• Treatment involved a multidisciplinary approach with an initial focus on surgical debulking and hyperthermic intraperitoneal chemotherapy, tailored by findings suggestive of pancreatic adenocarcinoma.
• The patient’s functional decline after initial chemotherapy magnified the challenges in managing severe PMP cases, particularly those not stemming from typical appendiceal origins.

Pseudomyxoma peritonei (PMP) is an internationally recognized rare disease with an incidence of 2–4 per million; the incidence is higher in females, approximately 2–3 times that of males.

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