Pseudomyxoma peritonei is a rare condition resulting from rupture of a mucocele of the appendix, a mucinous ovarian cyst, or a mucin-secreting intestinal or ovarian adenocarcinoma. The abdomen becomes filled with masses of jelly-like mucus. It was first described by Karl F. Rokitansky in 1842, and has an incidence of approximately 1 case per million of the population per year. The condition is characterized by an extensive spread of a mucin-secreting neoplasm along the peritoneal surfaces, which can present as an appendiceal tumor, an ovarian mass or mucinous ascites. Cytoreductive surgery and peri-operative intraperitoneal chemotherapy are the current standard treatment for selected patients with peritoneal surface spread of appendiceal primary tumors. We report the rare case of pseudomyxoma peritonei manifesting as umbilical hernia, diagnosed by abdominal ultrasound-guided biopsy.