Ocena roli badania zjawiska mimikry naczyniowej” i g sto ci mikronaczyń w nowotworach z o liwych jajnika u kobiet

Introduction: Neoplastic cells of various malignant tumours may induce formation of “vascular channels”which are not lined with endothelium. This phenomenon has been called “vasculogenic mimicry”. Objectives: To assess the frequency of vasculogenic mimicry in primary and metastatic malignant ovarianmasses in women and to compare it with microvascular density of the most vascularized parts of these tumours. Material and methods: Microvessel density (MVD) and PAS-positive structures representing “vascular channels”were assessed with the use of immunohistochemistry in a group of 66 women operated on because ofmalignant ovarian tumours. CD-34 antigen staining was used for MVD assessment and PAS-positive structureswere identified with modified Schiff’s reaction. Results: Mean age of the study group was 53.9 ±11.7 years (median 53 years, range: 23 to 86 years) and37 women (56.1%) were postmenopausal. There were 37 primary invasive ovarian cancers, 9 cancers of borderlinemalignancy, 10 tumours were metastatic to the ovary and 3 tumours were of non-epithelial origin (two folliculomasand one dysgerminoma). No PAS-positive structures were found in benign (n = 6) or in borderline tumours.Vasculogenic mimicry was found in 47% of primary malignant cancers, 50% of metastatic masses and 100% ofnon-epithelial malignant tumours. PAS-positive channels were most frequently found in high grade (G2 and G3)tumours and in advanced clinical stage cancers (FIGO stage III). Tumours with low MVD had vasculogenic channelspresent in 9 cases and absent in 7 cases. Ovarian malignant tumours with high MVD (> 39 microvessels per HPF)more frequently did not have vascular mimicry present (10 cases with PAS– and 5 cases PAS+). Interestingly, in thevicinity of spots with positive PAS reaction there were only a few CD-34 positive structures identified. Conclusion: Vasculogenic mimicry is a phenomenon that relatively frequently accompanies malignant ovarianneoplasms and can be used as a parameter characterizing the development of alternative vascular-likestructure formation in these tumours.