Year : 2010 | Volume
: 53 | Issue : 3 | Page : 414--417
Accuracy of intra-operative frozen section consultation in south of Iran during four years
Bita Geramizadeh, Taghi Rezai Larijani, Seyed-Mohammad Owji, Seyed Yahya Attaran, Simin Torabinejad, Fatemeh S Aslani, Ahmad Monabati, Perikala V Kumar, Seyed-Zeyaedin Tabei
Department of Pathology, Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Pathology, Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, PO Box: 71345-1864
Background: Accuracy of intraoperative frozen section diagnosis is an important part of quality control in surgical pathology. In this study we try to evaluate the frozen section diagnosis in our center, a referral center in southern Iran. Materials and Methods: During the four-year-period of study, all the frozen sections in the affiliated hospitals of Shiraz University of Medical Sciences were evaluated. Discrepant cases were studied to find out reasons for their inaccuracies. Results: In the four years, 759 frozen sections have been done, 25 of which showed discordant results. The most common site of frozen section and discrepancy was in central nervous system tumors. The reason for inaccuracy in frozen section diagnosis in 52% of cases was proved to be interpretative, 44% sampling error and the remainder due to lack of clinical information of the pathologist. Conclusion: Accuracy of our intraoperative consultation is comparable with other centers in Western countries. Most of the discrepancies can be prevented by providing more clinical information for the pathologist and more accurate sampling.
|How to cite this article:|
Geramizadeh B, Larijani TR, Owji SM, Attaran SY, Torabinejad S, Aslani FS, Monabati A, Kumar PV, Tabei SZ. Accuracy of intra-operative frozen section consultation in south of Iran during four years.Indian J Pathol Microbiol 2010;53:414-417
|How to cite this URL:|
Geramizadeh B, Larijani TR, Owji SM, Attaran SY, Torabinejad S, Aslani FS, Monabati A, Kumar PV, Tabei SZ. Accuracy of intra-operative frozen section consultation in south of Iran during four years. Indian J Pathol Microbiol [serial online] 2010 [cited 2020 Nov 25 ];53:414-417
Available from: https://www.ijpmonline.org/text.asp?2010/53/3/414/68250
Frozen sections (FS) continue to play an important role in surgical decisions and can help the surgeon determine the best surgical procedure. Since 1929, the accuracy of FS diagnosis has been investigated in many reports. 
Dankwa and Davis  have claimed that the frequency of FS-permanent section discrepancy is not reducible to less than 2%. However, this hypothesis was rejected by other studies with reported mean concordance frequency between 98.2 to 98.6%, indicating place for improvement in some institutions. ,,, Long term monitoring of frozen permanent section correlation is associated with sustained improvement in performance.  Accuracy of FS diagnosis should be evaluated every few years in each center to find the causes of error and try to decrease the discordant diagnosis between frozen sections and permanent fixed specimens. 
The correlation between intraoperative FS diagnosis and permanent sections should be an integral part of quality assessment activities in pathology departments. 
In this retrospective study, we compare the diagnosis of intraoperative FS consultation with the final diagnosis using permanent tissue section and analyze the reasons for discordant diagnosis.
Materials and Methods
During the period of four years, in different surgical sections, 759 frozen sections were reported (about 200 cases of Hirschprung's disease for ganglion cells and more than 400 donor liver transplant biopsies for steatosis were excluded). All the information was retrieved from the pathology archive and patients' clinical chart.
All the specimens were cut by cryocut (Leica instrument GmbH D-6907 Nussloch Germany) and stained by rapid hematoxyline and eosin stain. The main specimen was fixed in 10% buffered formalin for the permanent slides.
The results of frozen section and permanent section diagnosis were recorded and compared. Discrepant cases were categorized according to the site and analyzed to find out the reason for inaccuracy.
During the period of four years, 759 cases of frozen section were performed. It was among the 68000 surgical pathology cases. All the Hirschprung's cases for ganglion cells and donor liver transplant biopsies for steatosis were excluded from the study. The cases included in the study were neoplasm or suspected tumors, tumor margins, lymph nodes and etc. During the four years, 25 cases were discordant (3.3%) [Table 1] and [Table 2].
Considering the site, 505 cases were from the central nervous system (CNS); of these 14 showed discordant diagnoses between frozen and permanent sections (2.8%). The next common organ was ovary and, in 106 ovarian tumors, four discordant results were identified (3.5%)
The third common group was breast with 100 frozen sections and three discordant results (3%). The frozen sections of other less common parts of the body are summarized in [Table 1].
In the CNS tumors, all the frozen sections were performed for the diagnosis of tumor type. Most of the discordant cases (10 cases= 71%) were because of inability to differentiate between fibroblastic type of meningioma and schwannoma [Figure 1]a, b. In three cases, the discrepancy was between the diagnosis of low grade glioma and reactive gliosis [Figure 2]a, b and the last one was between high grade glioma and metastatic carcinoma [Figure 3]a, b.
In ovarian cancers, the frozen section discrepancies were because of difficulty in the diagnosis of malignancy in some of the surface epithelial tumors, i.e. benign, borderline and malignant surface epithelial tumor. In the breast tumor cases, all the discordant cases were among the ones for the evaluation of lymph node involvement by the tumor. The same result was found in the genitourinary, lung and thyroid tumor cases. The frozen section was also done to evaluate the adequacy of surgical margin resection. Over all, the concordant diagnostic frequency was 96.7% and the discordant frequency was 3.3%.
Accuracy of frozen section diagnosis in Shiraz University of Medical Sciences is comparable with most of the reports from College of American Pathologists' (CAP) control programs' results. , The discordant frequency in our study was 3.3% and the concordant rate was 96.7%. The discordant rate in different laboratories in one of the most recent reports of CAP has been as low as 1.1%, up to 5%. , Results from centers in UK show accuracy of 97.4%,  Japan 96%,  China 92.6 %  or Pakistan 97.1%. 
In our study, the reasons for discordance were mostly interpretative in 56% of cases, due to sampling error in 44% and lack of communication between pathologist and surgeon in the remainder. It is worthy to note that for all the cases, a permanent section of the frozen specimen was also studied to judge the reason of discrepancy i.e. interpretative vs. sampling error.
The most common discrepancy has been in CNS tumors (14 cases). Ten discrepant cases in CNS (71.3%) were in the spindle cells tumors, which should have been differentiated between meningioma and schwannoma. It means that we faced a spindle cell tumor in the brain with no evidence of malignancy and no clue to differentiate between a neurogenic tumor and meningioma. This common problem has also been previously reported.  In this situation, when based on histology at FS, the distinction cannot be made; it has been recommended to make a diagnosis of benign spindled cell tumor with a suggestion of main differential diagnosis. 
The other discrepancy, which was common in our center, has been between low-grade glioma and reactive gliosis (3 cases= 21.3%). This differential diagnosis is one of the most difficult differential diagnostic challenges in surgical neuropathology even in permanent sections.  There are several clues for this distinction, such as irregular cell distribution, hypercellularity, microcysts, nuclear pleomorphism, and perineural satellitosis; all of them are mostly applicable in permanent section and are very difficult to use in frozen section. 
The other discrepant case in our CNS frozen section was a metastatic tumor, which has been diagnosed as high grade glioma (Glioblastoma multiforme). In this case, lack of clinical information about the patient's history, was the reason for discrepancy. This problem is one of the most important causes in the intraoperative consultation in the CNS.  This differential diagnosis can be done using history and also some histopathologic criteria such as polygonal cell morphology and prominent nucleoli in metastasis and presence of vascular proliferation in glioblastoma multiforme. 
The second most common discrepancy in frozen sections has been in ovarian tumors. In these cases, frozen sections were performed to diagnose the presence or absence of malignancy as well as to determine the adequacy of resection by examining the surgical margins. All the four discrepant cases were in the first category. This problem has also been mentioned in previous reports. , Three of the discrepancies were the frozen section diagnosis of benign surface epithelial tumors, which in permanent sections proved to be borderline cases; the last one was diagnosed as malignant, but proved to be of borderline malignant potential.
All these cases were misdiagnosed mostly because of inadequate and improper sampling for frozen section specimen. , The third site of intraoperative frozen section consultation was the breast. Some of the breast frozen sections had been performed to diagnose the presence or absence of malignancy. Others were samples from lymph nodes and margins of malignant tumors for evaluation of the tumoral involvement. All our three discordant breast cases were among lymph nodes, which were diagnosed as negative in frozen section, but proved to be involved by several permanent cut sections. Therefore, the main cause of discrepancy in these cases was sampling error. It seems that in this situation more than one section should be examined to decrease false negative diagnosis in frozen section. 
The same situation was seen in our four discordant cases of lung, gastrointestinal, genitourinary tract and thyroid tumor frozen sections.
As highlighted by our study, errors in frozen sections are avoidable by more accurate interpretation, careful sampling and better communication between the pathologist and surgeon.
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