Squash preparation and frozen section in intraoperative diagnosis of central nervous system tumors.

OBJECTIVE

To investigate the diagnostic accuracy of squash preparation (smears) and frozen section (FS) in the rapid intraoperative diagnosis of central nervous system (CNS) tumors.

STUDY DESIGN

One hundred eighty-three CNS tumors were examined over a period of 18 months (January 1995-June 1996). All these were open biopsies, and the smear interpretation was compared with FS findings and paraffin section diagnosis.

RESULTS

In 183 tumors, squash preparation was satisfactory in 156 cases (85.2%), and the diagnostic accuracy was 89.7% (140/156). The accuracy of FS diagnosis was 90.4% (141/156).

CONCLUSION

The squash smear preparation is a fairly accurate and reliable tool in the rapid intraoperative diagnosis of CNS tumors. The accuracy of this technique is nearly as good as that of FS (P value = .9877). With the advent of stereotactic biopsies, the pathologist may have to depend entirely upon cytologic features for a definitive diagnosis.