The authors report a case of pseudomyxoma peritonei with gelatinous peritoneum in a 47-year-old-woman. The main symptom for discovery was a chronic pelvic abdominal pain. This disease is particularly rare. The gelatinous substance is often associated with a malignant ovarian tumor or appendicitis perforated. Currently, on the whole, an exploratory laparoscopy allows diagnosis, biopsies, and appendectomy. The treatment is essentially surgical. The prognosis depends on grade (1/3) and response to chemotherapy. This case was presented to the tumor board.