PSEUDO-DECIDUALIZATION AT THE SITE OF IMPLANTATION IN TUBAL PREGNANCY

The tissue from three tubal pregnancies at the site of implantation ha s been investigated with light and electron microscopy. Large seemingl y ''decidual'' cells were found to be present between the anchoring vi lli and the tissue of the uterine tubes. These cells are or cytotropho blastic column origin. Through discontinuities of the syncytiotrophobl ast they migrate into the underlying tissue were they grow and synthes ize large amounts of glycogen. It is suggested that these cells be nam ed pseudodecidual cells in order to distinguish them clearly from genu ine decidual cells to which they only bear a resemblance on the light microscopical level. The fibrinoid present at the utero-placental inte rface in eutopic implantation cannot be found in ectopic implantation. From this fact it is deduced that fibrinoid is formed through the act ion of genuine decidual cells and therefore must be of maternal origin .