Touch preps of products of conception for rule-out ectopic pregnancy a viable alternative to frozen section

Objectives: Tissue confirmation of the intrauterine location of a pregnancy can be difficult grossly, necessitating a frozen section diagnosis. First-trimester tissue is often scant and can be exhausted by frozen section. We examined 39 endometrial curettings performed for rule-out ectopic pregnancy by touch prep to examine the utility of cytopathology in documenting trophoblast or chorionic villi (products of conception [POC]). Methods: First-trimester curettage specimens sent to the Massachusetts General Hospital Pathology Departmentreceived a gross examination followed by a touch prep of the area most suspicious for villi. Touch preps were reviewed blinded to the final diagnosis and then compared. Results: Thirty-three of the 39 touch preps and histology specimens were concordant, including all 11 negative histology specimens and 22 of the 28 positive histology specimens. Conclusions: POC can be diagnosed by touch prep and may offer confirmation of grossly identified villi. Positive predictive value is 100%. Negative touch preps should receive further evaluation.