Touch Preps of Products of Conception for Rule-Out Ectopic Pregnancy:  A Viable Alternative to Frozen Section

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]).

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.

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.

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.