Frozen section examination of endometrial curettings in the diagnosis of ectopic pregnancy

Background.  The aim of our study was to determine the accuracy and validity of frozen section analysis of endometrial curettings in differentiating between abnormal intrauterine and ectopic pregnancies. Methods.  A retrospective analysis of the database of the Department of Obstetrics and Gynecology in our institute was performed from January 1998 to September 1999. In 70 women with a suspected ectopic pregnancy a diagnostic curettage was sent for frozen section examination because products of conception could not be identified macroscopically in the curettings. Routine paraffin fixation specimens were also prepared from the endometrial curettings. A frozen section diagnosis was considered correct if it concurred with the final pathologic diagnosis, and incorrect if it differed. The sensitivity, specificity, positive predictive value and negative predictive value of a frozen section in identification of conception products were calculated. Results.  Of the 70 frozen section studies the diagnosis was correct in 63 (90%), and incorrect in 7 (10%) cases. Of 50 specimens interpreted as negative on frozen sections (no products of conception noted), 6 (12%) were found to contain conception products on final pathologic review. One of the 20 (5%) specimens interpreted as positive by a frozen section failed to demonstrate products of conception on a final pathologic section. The sensitivity of frozen sections in the diagnosis of ectopic pregnancy was 76%, specificity 97.8%; positive predictive value 95%; negative predictive value 88% and accuracy 90%. Conclusions.  Frozen section examination is a rapid and accurate method for identifying products of conception in endometrial curettings, and may reduce delay in the diagnosis of an ectopic pregnancy and in the institution of therapy.