Pseudomyxoma peritonei (PP) associated with low-grade mucinous tumor of the appendix (Diffuse Peritoneal Adenomucinosis). The image shows almost atrophic-appearing mucinous epithelium lining a fibrous septa abutting mucin. The treatment of PP consists of cytoreductive surgery followed by intraperitoneal and systemic chemotherapy. Cytoreductive surgery includes resection of the involved areas of parietal peritoneum and viscera. It may require greater omentectomy, splenectomy, cholecystectomy, stripping of the right and left diaphragm, lesser omentectomy, appendectomy or right colectomy, partial or total gastrectomy, pelvic peritonectomy with resection of the recto-sigmoid, hysterectomy, and bilateral salpingo-oophorectomy. The prognosis is dependent upon completeness of the cytoreductive surgery. Five year survival rates drop if gross disease remains after surgery.