[1063] Placental Cell Islands, Origin and Significance in Abortions

RAM Rawson, E Silva. Cedars-Sinai Medical Center, Los Angeles, CA

Background: Literature on placental cell islands is very limited. The origin of cell islands is unclear but has been proposed to arise as dettachments from the septae that contain intermediate trophoblasts. The significance and purpose of these cell islands is unknown.
Design: Archived H&E slides from 28 abortions including 13 spontaneous and 15 therapeutic, matched by gestational age were reviewed. Immunohistochemical stains for CD10, hPL, and hCG were performed on 5 cases from each group.
Results: Both groups had a similar number of placental cell islands with a median of 8. There was no significant difference in the number of placental cell islands according to the age of the patients or weeks of gestation between the two groups. However, there was a significant difference in the number of cell islands with more intercellular fibrinoid material than cells in the spontaneous abortion 11 of 13 (85%), than in the therapeutic abortion 1 of 15 (7%). In the therapeutic abortions, most of the cells in the islands did not have fibrinoid material around them. The morphologic features and their association with syncytiotrophoblasts identify these cells as cytotrophoblasts. The cells from the islands of spontaneous abortions had similar features to those in the islands from therapeutic abortions with the exception of association with more fibrinoid material. Immunohistochemistry showed that the cells in the islands from both groups had similar staining. In staining with CD 10, 30% of cells were positive, and with hCG all cells were negative. However, hPL showed a negative reaction in cells without associated fibrinoid material, but 30% of the cells were positive in islands with associated fibrionoid material.
Conclusions: 1. Placental cell islands do not derive from the columns of the septae, but from cytotrophoblastic cells. This could be the origin of the villous intermediate trophoblasts and might explain cases of intermediate trophoblast tumors following treated choriocarcinoma. 2. The accentuation of the fibrinoid material and positive reaction for hPL in the placental cell islands is associated with spontaneous abortions. 3. We can not determine if the development of fibrinoid area in placental islands is the cause or effect of the abortions; however, since the only case in the therapeutic abortions with more fibrinoid changes had hyperemesis gravidarum, they might be involved in the pathogenesis of abortions.
Category: Gynecologic

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 153, Tuesday Afternoon