Challenges in diagnosing pseudomyxoma peritonei in a hepatitis B patient: A case report.

Background: Pseudomyxoma peritonei (PMP) is a rare condition, typically associated with the rupture of an appendiceal mucinous tumor. Due to its rarity and the complexity of its pathophysiology, PMP presents a significant diagnostic challenge.

Methods: A 59-year-old woman presented with a 6-month history of abdominal distension, anorexia, and significant weight loss. Her medical history was notable for chronic hepatitis B. She was initially treated for suspected cirrhosis, but her symptoms did not improve and therefore further diagnostic evaluation was needed. Methods: Initial imaging, including liver magnetic resonance imaging (MRI) and abdominal ultrasound, showed irregular liver margins and ascites, consistent with cirrhosis. However, subsequent diagnostic tests, including uterine MRI, positron emission tomography-computed tomography, and abdominal ultrasound, revealed features suggestive of PMP. Immunohistochemistry and histopathological examination of tissue samples confirmed low-grade mucinous adenocarcinoma of gastrointestinal origin, specifically from the appendix. Methods: The patient underwent cytoreductive surgery, and postoperative pathology confirmed mucinous adenocarcinoma originating from the appendix. The patient was also treated with intraperitoneal hyperthermic chemotherapy.

Results: The final diagnosis was PMP.

Conclusions: This case illustrates a rare presentation of PMP in a patient with co-existing hepatitis B, in which the initial diagnosis was biased towards cirrhosis: a more common cause of ascites in hepatitis B patients. This case highlights the importance of considering PMP in the differential diagnosis for patients presenting with unexplained ascites and abdominal distension.