[Pseudomyxoma peritonei secondary to a teratoma of the omentum with a mucinous component of borderline malignancy].

A mature cystic teratoma of the omentum occurred in a 37 years old woman who had an appendicectomy at the age of 8. This extragonadal teratoma contained a predominant mucinous glandular pattern of borderline malignancy, responsible for pseudomyxoma peritonei. Ovarian biopsies had only shown surface mucinous deposits at the time of the first laparotomy but two years later ovarian mucinous cystadenomas of borderline malignancy appeared. The patient developed intestinal obstruction, surround by mucinous retractile material and died four years and an half after initial diagnosis. This case is, to our knowledge, the first pseudomyxoma peritonei occurring from an extragonadal teratoma, the events chronology suggesting the secondary nature of the ovarian tumors.