Chorioangiomas - new insights into a well-known problem II. An immuno-histochemical investigation of 136 cases

Aims. Chorioangiomas are benign tumors of the hemochorial placenta. They are malformations or hamartomas, formed as a result of defective angiogenesis. They are of clinical importance due to their association with premature placental release and pre-eclampsia. Methods. Since a link has been established in neoplasias between tumor growth and an increased expression of angiogenic growth factors, 136 samples of chorioangiornas and 136 samples of tumor-free placental tissue were examined in terms of proliferation rate and expression of the growth factors angiopoietin-1 and -2, the angiopoietin-receptorTie-2, PDGF and the PDFG beta-receptor. Results. The chorioangiomas exhibited differing proliferation rates, whereas tumor-free placental tissue barely proliferated at all. Angiopoietin expression was - morphologically - considerably higher within the chorioangiomas than in the comparison placentas; morphological amounts of the Tie-2 receptor were identical in all samples. Expression of PDGF and its receptor was the same for chorioangiomas and tumor-free placentas. Conclusions. According to this study and the current literature in the field of hamartomas and some neoplasia, we can assume that increased growth factor expression plays a role in the formation of chorioangiomas, since it stimulates proliferation in a wide variety of cell compartments.