Immunohistochemical demonstration of placental hormones in the diagnosis of uterine versus ectopic pregnancy.

The authors find that immunohistochemical demonstration of placental hormones in endometrium is useful in the identification of trophoblast independent of the presence of chorionic villi. Human chorionic gonadotropin (HCG) and human placental lactogen (HPL) are markers for trophoblastic cells. The markers were studied in 21 cases of gestational endometrium without villi in which the clinical differential diagnosis was ectopic pregnancy versus missed or incomplete uterine abortion. Trophoblastic cells were identified in four cases by routine microscopy and in an additional seven cases using the markers. In none of these cases was there a subsequent demonstration of ectopic pregnancy. In six of the ten negative cases, ectopic pregnancies subsequently were removed. Thus, the use of these hormone markers in endometrial specimens increases precision in the diagnosis of uterine versus ectopic pregnancy.