[Ovarian tumors of low malignant potential: an intra- and retroperitoneal disease?].

Between 1987 and 1992, 13 patients underwent surgery for ovarian tumours of low malignant potential at the First Department of Gynaecology and Obstetrics of the University of Munich. In addition to intraperitoneal surgery, pelvic and para-aortic lymphadenectomy were conducted. In 8 of 11 tumours of the serous type, we found a microscopic extension extending beyond one ovary. In accordance with Russell and other investigators, we consider these alterations to be a disease of multicentric origin. In 3 cases we found within the lymph nodes similar structures to those we had found intraperitoneally, and described these as metastases. In 5 cases, we considered the epithelial lesions in lymph nodes to be mesothelial glandular inclusions. Two of those showed marked proliferations with occasional atypia, so they could be mistaken for metastases. In one case, we found proliferating glandular inclusions adjacent to tumour metastases. Altogether, we identified epithelial lesions within lymph nodes in 6 of 11 cases of serous ovarian tumours of low malignant potential. We call these lesions "tertiary Müller'sches System", independent of whether they are in situ mesothelial proliferations or a result of lymphatic transport of endometrial or tubal glands. Future studies must focus on the question of whether metaplastic and, in particular, neoplastic alterations of these structures have the same prognostic significance as lymph node metastases of ovarian carcinomas.