Accuracy of frozen section in determining meningioma subtype and grade

Usefulness and limitations of intraoperative pathological diagnosis using frozen sections for spinal cord tumors

BACKGROUND

Intraoperative pathological diagnosis has a major influence on the intra- and postoperative management of spinal cord tumors. Thus, the aim of this study was to assess the reliability of intraoperative pathological diagnosis for spinal cord lesions by comparing it with the final pathological diagnosis and to determine its usefulness and limitations.

METHOD

Three-hundred and three consecutive patients (mean age, 53.9 years) with neoplastic spinal cord lesions who underwent initial surgery between 2000 and 2021 were included. The anatomical locations of the spinal cord tumors and the implementation rate of intraoperative pathological diagnosis in each tumor type were evaluated. As the primary outcome, we determined the concordance rates between the intraoperative pathological diagnosis and the final diagnosis. When the intraoperative pathological diagnosis and final diagnosis were the same, the diagnosis was defined as a "match." Otherwise, the diagnosis was defined as a "mismatch."

RESULTS

The overall implementation rate of intraoperative pathological diagnosis was 53%, with implementation rates of 71%, 45%, 47%, and 50% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively. The overall concordance rate was 87.6%, with concordance rates of 80%, 95%, 75%, and 90% for intramedullary, intradural extramedullary, extradural, and dumbbell tumors, respectively (p < 0.05). The diagnoses of ependymomas, low-grade astrocytomas, and high-grade astrocytomas was occasionally difficult among intramedullary tumors. Among intradural extramedullary tumors, differentiation between grade 1 meningioma and high-grade meningioma was difficult using intraoperative pathological diagnosis.

CONCLUSIONS

Surgeons must recognize the lower accuracy of intraoperative pathological diagnosis for intramedullary and extradural lesions and make a final decision by considering the intraoperative gross findings, preoperative clinical course, and imaging.

Rapid Immunohistochemistry Based on Ultrasonic Thermal Steam Heating for Improvement of Intraoperative Diagnosis

OBJECTIVES

To evaluate the role of rapid immunohistochemistry (RIHC) based on ultrasonic thermal steam heating in improving diagnostic accuracy of intraoperative frozen section diagnosis and to recommend RIHC antibody panels for pathologic differential diagnosis.

MATERIALS AND METHODS

RIHC based on ultrasonic thermal steam heating was tested for intraoperative frozen diagnosis with difficulty in diagnosis, and all slides were reviewed and compared with the final diagnosis. Ninety-three cases of surgical specimens involving RIHC examination were studied. Discordance rates with paraffin immunohistochemistry were calculated.

RESULTS

In 93 cases where RIHC was performed, 85 cases (91%) were proven to be helpful for the diagnosis. A total of 58 antibodies were used for RIHC 276 times, of which 19 antibodies were not effective 25 times. Fifteen RIHC antibody panels are recommended based on staining stability and utilization frequency.

CONCLUSION

After improving the staining method, ultrasonic thermal steam heating RIHC is practical, convenient, and cost-effective, making it suitable for use in any pathology department with routine immunohistochemistry reagents. It plays an important auxiliary role in improving the accuracy of intraoperative rapid pathologic diagnosis.

Experimental study of different dehydration methods in the process of preparing frozen brain sections

This study aimed to provide a recommendable protocol for the preparation of brain cryosections of rats to reduce and avoid ice crystals. We have designed five different dewatering solutions (Scheme 1: dehydrate with 15%, 20%, and 30% sucrose-phosphate-buffered saline solution; Scheme 2: 20% sucrose and 30% sucrose; Scheme 3: 30% sucrose; Scheme 4: 10%, 20%, and 30% sucrose; and Scheme 5: the tissue was dehydrated with 15% and 30% sucrose polyacetate I until it sank to the bottom, followed by placement in 30% sucrose polyacetate II) to minimize the formation of ice crystals. Cryosections from different protocols were stained with Nissl staining and compared with each other by density between cells and the distance of intertissue spaces. The time required for the dehydration process from Scheme 1 to Scheme 5 was 24, 23, 24, 24, and 33 h, respectively. Density between cells gradually decreased from Scheme 1 to Scheme 5, and the distance of intertissue spaces was differentiated and irregular in different schemes according to the images of Nissl staining. We recommend the dewatering method of Scheme 4 (the brain tissues were dehydrated in 10%, 20% and 30% sucrose solution in turn until the tissue samples were completely immersed in the solution and then immersed in the next concentration solution for dehydration).

The emerging role of intraoperative flow cytometry in intracranial tumor surgery

Intraoperative flow cytometry has been recently emerged as a novel and promising tool for intracranial tumor surgery. Herewith, we discuss the role of intraoperative flow cytometry for the identification of gliomas boundaries, which may permit maximal resection and better prognosis. We also discuss its role in assessing tumor's grade of malignancy, both in adults and children and the prognostic information that may provide. Finally, intraoperative immunophenotypic analysis opens new horizons for flow cytometry. By evaluating tumor's specific cluster differentiation markers a diagnosis, within minutes, of certain tumor type can be achieved and additional information for therapeutic guidance can be provided.