Comparison of ThinPrep and conventional smears in detecting carcinoma in bile duct brushings

Bile duct brushing cytology is a common procedure for the exclusion of adenocarcinoma in the bile duct. The authors evaluated the use of ThinPrep (TP) to determine whether the information obtained is equivalent to that found with conventional smear cytology (CS).

Thirty-eight prospectively collected endoscope retrograde cholangiopancreatography-guided bile duct brushing samples were split in the following manner. First, two to four CS were prepared and immediately spray-fixed or wet-fixed. Second, the remaining sample was rinsed in PreservCyt (Cytyc Corp., Boxborough, MA). In the laboratory, one TP slide was prepared from each sample. TP and CS were stained by routine Papanicolaou stain. For the current study, TP and CS were reviewed independently by two cytopathologists. The diagnoses made by the two methods were compared with the final histology.

The cytologic diagnoses for both TP and CS were categorized into five main groups: 1) unsatisfactory, 2) negative, 3) reactive, 4) suspicious for malignancy, and 5) malignant. The diagnoses on the 38 TP bile duct brushings and CS were categorized as follows: 1) unsatisfactory-2, 4; 2) negative-7, 4; 3) reactive-10, 14; 4) suspicious for malignancy-9, 9; and 5) malignant-10, 7, respectively. Histologic follow-up was available in 14 cases (reactive-4, suspicious for malignancy-1, and malignant-9). The sensitivity was 77% for TP and 66% for CS. The specificity was 100% for both methods.

The two methods described in the current study detected equivalent disease on bile duct brushings. TP was found to provide better preservation and cytologic detail. However, the diagnostic criteria may require modification.