Acıbadem Üniversitesi Sağlık Bilimleri Dergisi 2010 , Vol 1, Issue 1
Intraoperative Diagnosis In Neurosurgical Resection Material and Stereotactic Brain Biopsies: Criteria For Success and Failure
Aydın Sav
Acıbadem Üniversitesi Tıp Fakültesi, Patoloji Anabilim Dalı, İstanbul, Türkiye Purpose: As a diagnostic and therapeutic tool intraoperative diagnosis (IOD) is widely used both in surgical resection (SR) and stereotactic biopsy (STX) approaches to nervous system. In this study sensitivity, specificity and overall accuracy of IOD's were analyzed.

Material: Techniques known as imprint and squash preparation diagnoses were reevaluated and results were compared with that of paraffin section diagnoses in a cohort formed by neurosurgical SR (n=529) and STX (n=368)[total=897] those were retrieved form archival material of Marmara University Neurological Sciences Institute, pathology laboratory in a period of 1995-2003.

Findings: Specificity values were found to be 98% and 91% in SR and STX biopsies respectively. Sensitivity rates were 99.2% and 97 and overall accuracy rates were 97.2/ and 97%. It was also clearly demonstrated factors eff ecting sensitivity in resected material were mainly inflammatory lesions, normal pituitary tissue, neuronal- glial tumors and abscess whereas reactive changes and proliferations and infectious conditions, i.e., abscess and cerebritis in STX. However it was found factors aff ecting specificity were consisted of metastasis, encephalomalasia, lymphoma/leukemia, pilocytic astrocytoma and normal neural tissue in SR. Mean time for intraoperative diagnosis was found to be 20.2 minutes.

Discussion:
I. What are the main diagnostic pitfalls?

Unavoidable sampling errors, lack of relevant criteria in tumor grading; improper sampling of tumor components; inability of identification of cell types in high grade tumors; misinterpretation of vascular proliferation as endothelial proliferation; insufficient clinical and radiological data; misinterpretation of radiation induced reactive changes as neoplastic alterations; misinterpretation of inflammation induced necrosis and reactive atypia as neoplastic features; misinterpretation of low grade neoplastic lesions as reactive changes; lack of exfoliation of neoplastic cells in matrix rich lesions.

II. How to avoid failures?

Close cooperation with neurosurgeon and neuroradiologist; well equipped pathology laboratory in or around operating room; experienced (neurosurgery, neuroradiology and neuropathology) teamwork. Keywords : intraoperative diagnosis, frozen section, neuropathology, stereotactic biopsy, intraoperative neurocytology