Pseudomyxoma is a rare disease characterized by the accumulation of mucus in the abdominal cavity. It is generally caused by a malignant tumour or peritoneal implantation from ruptured benign cysts or appendicular disease. The Mucus sets on the peritoneal surface and successively it stratifies onto organs. Successively its solidification could give compression on vascular structures, hepatic hilum and intestinal ansae. We report a case of a male patient 65 years old who came in under observation in March 2001. The patient stated he had an abdominal pain in the right iliac *fossa (che cosè??) three months before and since then he had had many episodes of abdominal pain. CT scan demonstrated the presence of a big gelatinous mass, which involved the abdominal cavity. The patient underwent surgical operation in which were made cholecystectomy, omentectomy, peritonectomy, total colectomy and extirpation of surgical surface also an intraoperative hyperthermic chemoterapy for 30 minutes was carried out. The patient had no complications and was discharged 10 days after surgery. By now, 72 months after surgery the patient is well and without disease. Peritoneal pseudomixoma is a very rare pathology. In our opinion surgery is the best treatment associated to an intraoperative hyperthermic chemotherapy and an adjuvant chronomodulated systemic chemotherapy.