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ORIGINAL ARTICLE
Year : 2018  |  Volume : 14  |  Issue : 6  |  Page : 1176-1179

Importance of intraoperative consultation for the diagnosis of central nervous system lesions and evaluation of its diagnostic accuracy


Department of Pathology, Gujarat Cancer and Research Institute, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat, India

Date of Web Publication28-Nov-2018

Correspondence Address:
Mitul Modi
Department of Pathology, Gujarat Cancer and Research Institute, Civil Hospital Campus, Asarwa, Ahmedabad - 380 016, Gujarat
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-1482.191034

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 > Abstract 


Context: Intraoperative consultation frozen section (FS) provides a surgeon background and management plan for surgery. Surgeons' and pathologists' coordination between each other including their departments' cooperation for FS management is very important. The role of FS in the intraoperative consultation is important. It is always advisable to consult an experienced histopathologist specially trained for CNS lesions for intraoperative consultation.
Aims: Frozen section (FS) diagnosis provides surgeons, physicians, and pathologists a provisional diagnosis to plan out their management plan. By this study, we intended to evaluate the importance of intraoperative consultation-FS diagnosis in central nervous system (CNS) lesions. In this study, the diagnostic accuracy and the various limitations of using FS of CNS tumors were determined.
Subjects and Methods: In this study, we analyzed retrospectively, the results of FS and final diagnoses of all CNS tumors were made at our institute for the duration of 1 year from July 2014 to June 2015.
Ethical Standards: We all authors state that all human studies have been approved by the Institutional Ethics Committee. We all authors also gave our informed consent before their inclusion in the study. Details that might disclose the identity of the subjects under study have been omitted.
Results: We studied 252 cases of age group from 1 to 76 years. Out of which, 155 (61.50%) cases had complete concordance between FS and final diagnosis, 77 (30.5%) cases had a partial concordance, and 20 cases (8.0%) were discordant. Considering the concordant and partially concordant cases, the accuracy rate was 92.0%, sensitivity was 93.42%, specificity was 91.66%, and positive and negative predictive values were 94.66% and 59.45%, respectively.
Conclusions: A Kappa agreement score of 0.75 (substantial agreement score) showed high concordance for FS results with the permanent section. We came to the final conclusion that high sensitivity and specificity were seen with FS diagnosis in the CNS tumors.

Keywords: Central nervous system tumors, frozen section, statistics


How to cite this article:
Modi M, Nilkanthe R, Trivedi P, Shah A, Shah J, Chaudhari J. Importance of intraoperative consultation for the diagnosis of central nervous system lesions and evaluation of its diagnostic accuracy. J Can Res Ther 2018;14:1176-9

How to cite this URL:
Modi M, Nilkanthe R, Trivedi P, Shah A, Shah J, Chaudhari J. Importance of intraoperative consultation for the diagnosis of central nervous system lesions and evaluation of its diagnostic accuracy. J Can Res Ther [serial online] 2018 [cited 2018 Dec 13];14:1176-9. Available from: http://www.cancerjournal.net/text.asp?2018/14/6/1176/191034




 > Introduction Top


Intraoperative consultation frozen section (FS) provides a surgeon background and management plan for surgery. Surgeons' and pathologists' coordination between each other including their departments' cooperation for FS management is very important. FS diagnosis helps the surgeon to determine the best procedure and the end-point of the operation in central nervous system (CNS) lesions specifically.[1],[2] Many studies have confirmed the accuracy of FS diagnosis for the assessment of the CNS lesions, with acceptable sensitivity.[3],[4] We retrospectively studied the reliability of FS diagnosis for CNS lesions at our institute over a period of 1 year.


 > Subjects and Methods Top


We studied 252 cases and analyzed retrospectively the results of FS. Final diagnoses of all CNS lesions were made in at our institute for the duration of 1 year, i.e. from July 2014 to June 2015. According to sample size and consistency, representative sections were taken by an attending pathologist during FS consult. Various preparations were used such as touch, crush, imprint, and squash. After proper cooling in a cryostat, frozen tissue was made into small sections. After proper formalin fixation, additional representative sections were taken for paraffin embedding and routine hematoxylin and eosin staining. After an accurate microscopic examination of all slides, consultant histopathologist gives a definitive diagnosis. All the cases were graded into three degrees of diagnosis concordance to clarify the accuracy of intraoperative diagnosis.

All pathological reports were reviewed retrospectively. There was no ethical problem during this study.


 > Results Top


Around 252 cases were reviewed from the Department of Pathology at our institute. The results from the permanent sections were used as a gold standard. The reports of frozen and permanent sections were evaluated according to the status of cases as benign or malignant and histological type of the lesions. In all the cases, the definitive diagnosis was made after a thorough microscopic examination of all slides.

The overall sensitivity, specificity, false positivity, false negativity, positive predictive value (PPV), and negative predictive value (NPV) of FS were determined according to the type of the lesions and the accuracy of histological tumor types. Histological diagnosis was made according to the criteria set forth in pathology textbooks for the diagnosis of CNS tumors.[5],[6] For histological typing of tumors, Armed Forces Institute of Pathology and the WHO classification of CNS tumors recommendations were followed.[6]

The cases were graded into three degrees of diagnosis concordance to clarify the accuracy of FS diagnosis as follows:

  1. Complete concordance: On evaluation FS diagnosis and the final diagnosis were exactly synonymous
  2. Partial concordance: FS diagnosis was not incorrect but was too broad to qualify as complete concordance; and
  3. Discordant or nonconcordance.


FS diagnosis was incorrect and different from the final diagnosis. All statistical analyses were performed using Microsoft Excel 2010. To evaluate the agreement of the methods, we utilized sensitivity, specificity, NPV, and PPV. To describe data, we used mean, standard deviation, median, and percent.

Out of all cases, 159 (63.1%) were male, and 93 (36.9%) were female. In addition to that, 155 cases (61.5%) had complete concordance between FS and final diagnosis, 77 cases (30.5%) had partial concordance, and 20 cases (8.0%) were discordant. In all the cases, the age of the patients ranged from 1 to 76 years (mean age - 38.5-year-old). Considering the concordant and partially concordant cases, following statistical results were obtained.

The accuracy rate was 90.11%, sensitivity was 93.42%, and specificity was 91.66%.

Positive and NPVs were 94.66% and 59.45%, respectively.

A kappa agreement score of 0.75 (suboptimal agreement) shows high concordance of FS results with permanent sections [Figure 1].
Figure 1: Graphical distribution of various central nervous system lesions according to various brain location

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Lesions were located in frontal lobe 80 (31.7%), temporal lobe 40 (15.8%), sellar region 30 (11.9%), parietal lobe 27 (10.7%), occipital lobe 49 (19.4%), and cerebellopontine angle 26 (10.3%) [Table 1].
Table 1: Summarize the number of cases according to the type of lesion and degree of concordance

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The partially concordant cases (77 cases) included those in which FS diagnoses were not incorrect but were too broad to qualify as a complete concordance. Examples of these cases are as follows:

FS - glial tumor, permanent: Astrocytoma or ependymoma; FS - low-grade glial tumor, permanent: Ganglioglioma; FS - positive for malignancy, permanent: Metastatic tumor; FS - benign spindle cell tumor, permanent: Schwannoma; FS - malignant round cell tumor, permanent: Lymphoma; FS - granulomatous lesion, permanent: Tuberculous lesion or tuberculoma; FS - inflammatory process, permanent: Fungal inflammation [Table 2].
Table 2: Summarizes discordant cases

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There were cases having incomplete or inaccurate data, which were put off. For example, six cases astrocytoma, two cases of dysembryoplastic neuroepithelial, one case of medulloblastoma, one case of hemangioma, one case of ependymoma, one case of choroid plexus papilloma, and one case of rhabdoid meningioma.


 > Discussion Top


Through intraoperative consultation (FS), pathologists can provide surgeons a diagnosis, which will help surgeon to decide a subsequent surgical approach. In addition to that, FS diagnosis can inform the surgeon as to whether the biopsy is taken from the appropriate area and the adequacy of the specimen, which in turn can help the pathologist to make a final diagnosis.[2]

The majority of discordancies between FS and the permanent diagnoses were seen in astrocytoma, CNS malignancies, ependymoma, metastatic tumors, meningioma, and rhabdoid tumor.[3],[7]

Most diagnostic accuracy was 92.4% in “Talan Hernilovic” study[8] and 95% in “Roessler” study[9] with 89% complete concordance among 4172 patients.[9] In a referral center in Pakistan, the diagnostic accuracy was 88.9% in CNS neoplasms for 171 cases.[4]

The most accurate FS diagnoses were made in cases of meningioma (97.9%), metastasis (96.3%), and glioblastoma (95.7%). “Thomas Plesec et al.” study had <:3% discordancy among 2156 cases during an 8-year period in his study.[7] Approximately 80% of the discrepant cases, most of which were lymphoma, astrocytoma versus oligodendroglioma, reactive versus neoplastic process, and misclassification of tumor grading.[7] A French study of 1315 cases was found having 96.6% concordance between FS and permanent diagnoses [Table 3].
Table 3: Comparison of accuracy and other statistical parameters between our study and other studies

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Our results showed a high accuracy for FSs in the diagnosis of CNS lesions (92%) when concordant, and partially concordant cases were included and considering partially concordant cases were correct but not as accurate as completely concordant diagnoses [Table 4].
Table 4: Comparison of concordance and discordance between our study and other studies

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In our study, 155 of 252 cases were in complete concordance. Most of our discordant results were in astrocytic tumors (five cases), followed by CNS metastatic tumors, primitive neuroectodermal tumor, medulloblastoma, and ependymal tumors. A total of 84% (21 cases) of meningiomas were diagnosed correctly with FS analysis.

There were multiple factors which contributed to inaccurate FS diagnoses, majority of which were improper slide preparation, lack of pathologist expertise, and inadequate sampling. The lack of communication between pathologists and surgeons was one strong factor among that. Because of all these factors, sometimes, it is difficult to diagnose cytoplasmic processes and fibrillary patterns in FS slides, which makes it impossible to differentiate glial tumors from carcinoma, lymphoma, and melanoma.

Wrong FS diagnosis of astrocytoma in some cases could be due to the improper method of staining and cutting, which in turn could have disrupted cellular morphology (two of our cases).[5]

The diagnosis of ependymoma by FS is easy; however, sometimes because of the presence of perivascular rosettes makes it difficult to differentiate it from medulloblastoma. Pituitary adenoma could have been misdiagnosed as malignant round tumors in FS due to round monomorphic cells in the pituitary adenoma as was the case in one of our patients.


 > Conclusions Top


Admittedly, FS diagnosis carries an enormous amount of importance. Appropriate communication between pathologists and neurosurgeons with adequate information about the radiologic findings is helpful to minimize FS misdiagnosis. The results of our study show a high percentage of accuracy in the intraoperative diagnosis of CNS lesions. Although inadequate biopsy samples, pathologist misguidance, suboptimal FS preparation, and inadequate information radiologic findings were major causes of discrepancies in our study, the role of FS in the intraoperative consultation is important. It is always advisable to consult an experienced histopathologist specially trained for CNS lesions for intraoperative consultation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 > References Top

1.
Taxy JB, Anthony G. Biopsy Interpretation: The Frozen Section. 1st ed. China: Lippincott Williams and Wilkins; 2010. p. 301-3.  Back to cited text no. 1
    
2.
Somerset HL, Kleinschmidt-DeMasters BK. Approach to the intraoperative consultation for neurosurgical specimens. Adv Anat Pathol 2011;18:446-9.  Back to cited text no. 2
    
3.
Regragui A, Amarti Riffi A, Maher M, El Khamlichi A, Saidi A. Accuracy of intraoperative diagnosis in central nervous system tumors: Report of 1315 cases. Neurochirurgie 2003;49(2-3 Pt 1):67-72.  Back to cited text no. 3
    
4.
Ud Din N, Memon A, Idress R, Ahmad Z, Hasan S. Central nervous system lesions: Correlation of intraoperative and final diagnoses, six year experience at a referral centre in a developing country, Pakistan. Asian Pac J Cancer Prev 2011;12:1435-7.  Back to cited text no. 4
    
5.
Burger PC, Scheithauer BW. Tumors of the central nervous system. In: AFIP Atlas of Tumor Pathology Series 4. Washington, D.C.: American Registry of Pathology; 2007.  Back to cited text no. 5
    
6.
Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97-109.  Back to cited text no. 6
    
7.
Plesec TP, Prayson RA. Frozen section discrepancy in the evaluation of central nervous system tumors. Arch Pathol Lab Med 2007;131:1532-40.  Back to cited text no. 7
    
8.
Talan-Hraniloviæ J, Vuèiæ M, Ulamec M, Belicza M. Intraoperative frozen section analysis in of the central nervous system and pituitary gland pathology. Acta Clin Croat 2005;44:217-21.  Back to cited text no. 8
    
9.
Roessler K, Dietrich W, Kitz K. High diagnostic accuracy of cytologic smears of central nervous system tumors. A 15-year experience based on 4,172 patients. Acta Cytol 2002;46:667-74.  Back to cited text no. 9
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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