Intraoperative Consultation in the Diagnosis of Pediatric Brain Tumors

The utilisation of fMRI for pre-operative mapping in the paediatric population with central nervous system tumours: a systematic review

BACKGROUND

Functional MRI (fMRI) is a well-established tool for pre-operative planning, providing neurosurgeons with a roadmap of critical functional areas to preserve during surgery. Despite its increasing use, there is a need to compare task-based (tb-fMRI) and resting-state fMRI (rs-fMRI) in the peadiatric population to comprehensively evaluate the existing literature on the use of fMRI for pre-operative mapping in pediatric patients, comparing tb-fMRI and rs-fMRI.

METHODS

Two databases were searched for relevant studies published before July 2024 following the PRISMA guidelines. Eleven studies were selected and comprised 431 participants: 377 patients with different types and locations of brain tumours, and 54 healthy controls (HC).

RESULTS

Results indicate that tb-fMRI could reliably locate the eloquent cortex with more than an 80% success rate. Furthermore, results were comparable with intraoperative mapping. Two studies reported that 68-81% of patients did not develop deficits in the postoperative period. Results also found that rs-fMRI can fill the gap in the situation of paediatric patients when other techniques do not apply to younger patients.

CONCLUSION

This study suggests that tb-fMRI is more effective for pre-operative mapping in pediatric patients, offering precise localisation of critical brain functions and enhancing surgical planning. Although rs-fMRI is less demanding and compatible with light sedation, it lacks the specificity needed for accurate identification of language, sensory, and motor areas, which limits its clinical relevance. rs-fMRI can aid in function-preserving treatments for brain tumour patients and reduce the need for invasive procedures. Combining tb-fMRI with intraoperative mapping optimizes precision and safety in pediatric-neurosurgery.

Primary adult choroid plexus carcinomas: a single-center experience with a systematic review

Objective

Primary adult choroid plexus carcinomas (PACPCs) are extremely rare brain tumors. The existing literature primarily comprises case reports, which limits our understanding of this uncommon disease. This study aims to describe the clinical characteristics and prognosis of PACPCs, as well as to identify optimal treatment strategies.

Methods

We conducted a comprehensive analysis of clinical data from 7 patients with PACPCs who underwent surgical treatment at the Department of Neurosurgery, Beijing Tiantan Hospital, between March 2011 and March 2023. Additionally, a thorough search of the PubMed database was performed using the keywords "choroid plexus carcinoma" or "choroid plexus carcinomas" within the time frame of August 1975 to April 2023, which yielded a total of 28 identified cases. Subsequently, we evaluated risk factors for progression-free survival (PFS) and overall survival (OS) based on the pooled cases.

Results

The pooled cohort, consisting of 7 cases from our institution and 28 cases from the literature, included 20 males and 15 females with a mean age of 44.3 ± 14.7 years (range: 21-73 years). Gross-total resection (GTR) and non-GTR were achieved in 22 (62.9%) and 13 (37.1%) patients, respectively. Radiotherapy and chemotherapy were administered to 29 (90.6%) and 13 (40.6%) patients, respectively. After a mean follow-up of 21.0 ± 26.7 months (range: 2-132 months), 18 patients were alive, and 11 patients had died. The multivariate Cox regression model demonstrated that non-GTR (HR 5.262, 95% CI 1.350-20.516, p=0.017) was a negative prognostic factor for OS. However, we did not find any risk factors for PFS.

Conclusion

Complete surgical resection should be considered as the primary treatment approach for this rare disease. Chemotherapy and radiotherapy appear to have limited effectiveness in treating this condition. Further research with large cohorts is needed to validate our conclusions.

Next generation DNA sequencing of atypical choroid plexus papilloma of brain: Identification of novel mutations in a female patient by Ion Proton

Choroid plexus papilloma (CPP) is a rare benign tumor of the central nervous system that is usually confined to the cerebral ventricles. According to the World Health Organization, CPP corresponds to a grade I atypical CPP (a-CPP); however, it can become more aggressive and reach grade II, which can rarely undergo malignant transformation into a choroid plexus carcinoma (grade III). To the best of our knowledge, identification of these tumors mutations by next generation DNA sequencing (NGS) has not been yet reported. In the present study, NGS analysis of an a-CPP case was performed. Data were analyzed using Advaita Bioinformatics i-VariantGuide and Ion Reporter 5.6 programs. The results from NGS identified 12 novel missense mutations in the following genes: NOTCH1, ATM, STK36, MAGI1, DST, RECQL4, NUMA1, THBS1, MYH11, MALT1, SMARCA4 and CDH20. The PolyPhen score of six variants viz., DST, RECQL4, NUMA1, THBS1, MYHI1 and SMARCA4 were high, which suggested these variants represents pathogenic variants. Two novel insertions that caused frameshift were also found. Furthermore, two novel nonsense mutations and 14 novel intronic variants were identified in this tumor. The novel missense mutation detected in ATM gene was situated in c.5808A>T; p. (Leu1936Phe) in exon 39, and a known ATM mutation was in c.5948A>G; p. (Asn1983Ser). These novel mutations had not been reported in previous database. Subsequently, the quality statistics of these variants, including allele coverage, allele ratio, P-value, Phred quality score, sequencing coverage, PolyPhen score and alleles frequency was performed. For all variants, P-value was highly significant and the Phred quality score was high. In addition, the results from sequencing coverage demonstrated that 97.02% reads were on target and that 97.88% amplicons had at least 500 reads. These findings may serve at determining new strategies to distinguish the types of choroid plexus tumor, and at developing novel targeted therapies. Development of NGS technologies in the Kingdom of Saudi Arabia may be used in molecular pathology laboratories.

Cerebrospinal fluid cytology of choroid plexus tumor: A report of two cases

Choroid plexus tumors (CPTs) are relatively uncommon tumors of the central nervous system, constituting approximately 5% of all pediatric brain tumors. Although squash cytology of CPT has been described in literature, shedding of tumor cells into cerebrospinal fluid (CSF) has rarely been described. We report two such cases of atypical choroid plexus papilloma in a 5-month-old male child and a 12-year-old female child, where characteristic cytomorphology of CPT was noted in the CSF.

Role of Squash Cytology in Intraoperative Diagnosis of Spinal Lesions

Background:

Squash cytology for intra operative diagnosis of central nervous system (CNS) tumors is an immensely important modality. Though its role in brain lesions is unquestionable and has been proven in a number of studies, its utility for spinal lesions is still a grey zone.

Aims:

To assess the diagnostic accuracy of squash preparation in spinal lesions and its statistical significance (sensitivity, specificity, positive predictive value, negative predictive value) following histological confirmation.

Materials and Methods:

A total of 57 cases of spinal tumors were taken. May-Grunewald-Giemsa staining (MGG) and Hematoxylin-Eosin (H&E) were done in each one of them. Rest of the tissue was processed for histological diagnosis and results were compared.

Results:

In our study, histology was taken as the gold standard. By comparing the results, squash preparation had sensitivity of 95.75%, specificity 80.0%, positive predictive value (PPV)95.74%, and negative predictive value (NPV) 80.80%. Schwannoma was found to be the most prevalent tumor in the spine (17/57) in our study, followed by meningioma (13/57). Diagnostic accuracy for schwannoma was fairly high i.e. 92.3%, followed by meningioma (82.35%). Highest diagnostic accuracy was documented in intradural, extramedullary compartment.

Conclusion:

Inspite of having pitfalls and various limitations in case of spinal lesions, squash preparation is a rapid and easy method with fairly high diagnostic accuracy. So it can be reliably used as an intraoperative diagnostic tool in spinal lesions.

Evaluation of Intraoperative Cytological Smears for Diagnosis of Brain Tumors with Special Reference to Immunohistochemistry

Context:

Brain tumors are heterogeneous group of benign and malignant tumors of glial, meningeal, neuronal, embryonal, and lymphoid origin. Rapid intraoperative diagnosis of the nature of the tumor helps the surgeon to plan the extent of surgery and modify it accordingly.

Aims:

(1) To establish the validity and reliability of squash cytology in the intraoperative diagnosis of brain tumors. (2) To correlate with histopathological report and immunohistochemistry (IHC) profile.

Settings and Design:

Prospective, observational study.

Subjects and Methods:

prospective, observational study was conducted in the Department of Pathology in collaboration with the Department of Neurosurgery of a tertiary care hospital. One hundred and seven patients with symptomatic or radiologically detected brain tumors were included in the study. Intraoperative squash smears were stained with hematoxylin and eosin and rapid papanicolaou stain. Cytological diagnosis was recorded and communicated to the surgeon. Cytological findings were corroborated with histological findings subsequently. GFAP, Ki-67, and ER-PR IHC were used as additional markers.

Statistical Analysis Used:

Software used in statistical analysis of our study was MedCalc version 11.6 (Mariakerke, Belgium: MedCalc Software 2011).

Results:

A total of 107 cases were included in the study. Meningioma was the most common lesion. Overall sensitivity in our study to diagnose benign and malignant tumors was 94.7% and the specificity is 97.6% with positive and negative predictive value of 94.7% and 97.6%, respectively. Diagnostic accuracy was highest in pituitary adenoma.

Conclusions:

The combination of meticulous evaluation of clinical, radiological, and cytological findings helps in accurate and rapid diagnosis of brain tumors.

Correlation of intraoperative cytological and final histological diagnoses: a retrospective 10-year study of neurosurgical cases from Ibadan, Nigeria

OBJECTIVE

Intraoperative cytology is a cost-effective, rapid, and easy technique, and studies have shown good correlation between intraoperative cytology and histology. We undertook this study to compare the intraoperative cytology diagnoses of brain lesions made in our unit over a 10-year period with the definitive histological diagnoses. The aim was to determine the degree of accuracy of this procedure.

STUDY DESIGN

This is a retrospective study of intraoperative neuropathology consultation cytology smears or imprints and histology of 69 cases obtained over a 10-year period. Cytology smears were stained using both Papanicolaou and Giemsa. Histology sections were prepared from routine formalin-fixed paraffin-embedded tissue and stained using H and E method. Each of the smears and histology samples were assessed by at least two pathologists. Cytological diagnosis was correlated with final histological diagnosis. The sensitivity and specificity of cytological diagnosis was evaluated using final histological diagnosis as gold standard.

RESULTS

Correlation was strongest with inflammatory lesions followed by low-grade neoplasms. High-grade neoplasms also showed good concordance, but the degree of correlation was lower than in the other categories. Misdiagnosis was commonest with benign tumors.

CONCLUSION

Intraoperative cytology is a relatively simple, reliable, and accurate diagnostic technique and should be more commonly used, particularly in low-resource settings.

CNS intraoperative consultation: a survival guide for non-neuropathologists

Intraoperative consultations for central nervous system disease may be challenging due to limitations of sample size, lack of familiarity with neurosurgical procedures, or poor access to neuroimaging studies. Despite these challenges, the surgical pathologist is charged with determining if the tissue sample is representative of the pathologic process while ensuring that enough diagnostic tissue has been retained for routine histology, immunohistochemistry, fluorescence in situ hybridization, molecular testing, and in some cases, tissue banking. Here, we present basic methods and a practical approach for CNS intraoperative consultation including critical pre-analytic considerations that promote optimal tissue management.

Choroid plexus tumors: A clinico-pathological and neuro-radiological study of 23 cases

BACKGROUND

Choroid plexus tumors are intraventricular tumors derived from choroid plexus epithelium.

AIM

To study the choroid plexus tumors with reference to their clinical, radiological, and pathological features.

MATERIALS AND METHODS

The study was performed by the retrospectively reviewing the clinical, radiological, and pathological records of patients of choroid plexus tumors.

RESULTS

A total of 23 cases (11 males, 13 females) of choroid plexus tumor were diagnosed from 1997 to 2009. Fourteen patients were below 15 years of age. Raised intracranial pressure was the main presenting feature in all the cases. Tumor was located in lateral ventricle (n = 14; in 3 cases tumor was going into third ventricle), fourth ventricle (n = 7), and cerebellopontine angle (n = 2). Total tumor excision was achieved in 21 cases. The histopathology was suggestive of choroid plexus papilloma (n = 19), atypical choroid plexus papilloma (n = 1), and choroid plexus carcinoma (n = 2). Clears cell areas were noted in three cases. Other histopathological features observed were foci of calcification (n = 5), Psammoma bodies (n = 2), hemorrhage (n = 5), hyalinization (n = 2), and oncocytic changes (n = 1).

CONCLUSIONS

Choroid plexus tumors are intraventricular tumors arising from choroid plexus epithelium. The predominant clinical presentation is raised intracranial pressure. Surgery is the mainstay of treatment; histopathologically, they include choroid plexus papilloma, atypical choroid plexus papilloma, and choroid plexus carcinoma.

Feasibility and clinical utility of intraoperative consultation with frozen section in osseous lesions

Intraoperative consultation (IOC) with frozen section (FS) allows the surgeon to make therapy decisions during the operation. However, there is relatively little information on the use of IOC in skeletal lesions. We performed a retrospective study to examine the indications for IOC and compare the histological findings of FS and permanent paraffin section (PS) results to determine its clinical benefits. Ninety-seven consecutive cases evaluated between 2008 and 2011 were retrieved from IOC archives of our Pathology Department. In 79 % of the cases, there was no prior core needle biopsy (CNB), and IOC was performed to confirm the clinical or radiological diagnosis. In 5 (5 %) cases, no definitive result could be obtained with FS, and diagnosis was deferred. The reasons for a deferred diagnosis (DD) included poor section quality in two lipomatous lesions and the sample heterogeneity in the others. When adjusted for DD, FS and PS results showed 100 % concordance in terms of discriminating "benign vs. malignant" and defining diagnostic categories as "benign non-tumoral," "benign tumoral/tumor-like," "malignant primary tumor," "malignant metastatic tumor," or "hematopoietic malignancy." The presence of non-sclerotic osseous tissues does not have a significant adverse impact on the FS section quality and diagnosis made by FS. Thus, sections with diagnostic value can be obtained from bone lesions via FS. In this study, specific diagnoses were made in 88 % of the cases. We believe that IOC with FS can be safely performed in tertiary referral centers where there is a multidisciplinary team working in collaboration.

Intraoperative neurocytology of primary central nervous system neoplasia: A simplified and practical diagnostic approach

Intraoperative consultations may pose considerable diagnostic challenge to the neuropathologist in diagnosing primary and metastatic neoplasms of the central nervous system (CNS). Cytological preparations in the form of squash, touch, imprint or smears are few of the available modalities in addition to the frozen section (FS). Although the latter is superior in providing both histologic patterns and cytomorphologic details yet smears are of vital importance when tissue available is limited (stereotactic biopsy), scrutinisation of intercellular matrix (astrocytoma versus oligodendroglioma) and evaluation of discohesive cells (lymphoma, pituitary adenoma) and in inflammatory lesions. This review is intended to emphasize the value, applicability and limitations of neurocytology aiming to expedite the intraoperative smear-based diagnoses of CNS neoplasia as per the World Health Organization (WHO) classification. We recommend that whenever possible, both smears and FS should be examined concomitantly and in a correlative manner. In the unlikely event of a mismatch between the findings on smear and FS, intraoperative diagnosis is primarily based on FS, if adequate tissue is available. However, each case must be evaluated on its own merit and in difficult cases relevant differential diagnoses should be offered to facilitate surgical decisions and optimally triage patient management.

Intraparenchymal clear cell ependymoma

Clear cell ependymoma (CCE) is an uncommon variant of ependymoma having a predilection for the supratentorial region. Histologically, it bears an uncanny resemblance to oligodendroglioma, central neurocytoma, hemangioblastoma and metastasis from clear cell carcinoma. Here, we report a rare case of clear cell ependymoma in a 45-year-old male, which histomorphologically resembled anaplastic oligodendroglioma on intraoperative smears, frozen section and routine light microscopy. Immunohistochemistry, however, helped to arrive at the correct diagnosis. Unlike other clear cell tumors of the brain parenchyma, CCE is known to follow an aggressive course and, hence, obtaining a correct diagnosis is imperative since it has a direct therapeutic and prognostic connotation.

Image-guided frameless stereotactic biopsy without intraoperative neuropathological examination

OBJECT

Stereotactic biopsy is a safe and effective technique for the diagnosis of brain tumors. The use of intraoperative neuropathological examination has been routinely advocated to increase diagnostic yield, but the procedure lengthens surgical time, may produce false-negative and -positive results, and current biopsy techniques have a very low nondiagnostic rate. Therefore, the authors questioned the need for intraoperative histological evaluation.

METHODS

The authors prospectively studied all patients undergoing image-guided biopsy under the care of a single surgeon (P.L.G.) between July 2005 and October 2007. A Stryker neuronavigation system with a trajectory guide was used to plan a single trajectory, and, using a side-cutting biopsy cannula, multiple biopsy samples were taken from between 1 and 4 sites within the tumor. Tissue was inspected macroscopically by the surgeon and was only submitted for neuropathological assessment postoperatively.

RESULTS

One hundred thirty-four biopsies were performed during the study. A positive diagnosis was established in 133 cases (99.3%). One biopsy was negative (0.7%) and postoperative imaging (performed because the tissue was macroscopically normal) demonstrated inaccurate targeting of the lesion. Significant complications were seen in 3 patients (2.2%) who all had preoperative WHO performance scores of III or IV. Two patients suffered delayed deterioration and died due to probable surgical complications--one with thalamic glioblastoma multiforme (GBM) and one with gliomatosis cerebri. One patient with GBM suffered an intracerebral hematoma that was managed conservatively. Postoperative seizures were seen in 4 patients (3%), and 2 patients (1.5%) experienced a transient neurological deficit. Histological diagnosis showed a GBM in 64 cases, Grade III glioma in 19, Grade I or II in 23, metastasis in 10, lymphoma in 13, and other disease in 4. There were 32 patients discharged to home on the same day as surgery. Compared with the authors' previous retrospective audit into 127 biopsies, this technique showed improved diagnostic yield (99.3 vs 94.5%, p = 0.032) with fewer complications (2.2 vs 4.7% [not statistically significant]).

CONCLUSIONS

This technique of image-guided biopsy has high diagnostic yield with acceptably low morbidity and may be performed as a day case. Intraoperative neuropathological examination would not have increased the diagnostic yield further in this study, and its routine use may not be necessary. In the authors' department pounds sterling 70,350 (UK)/$114,522 (US) would have been saved by not using intraoperative neuropathology in this series. Therefore, intraoperative neuropathology should no longer be routinely recommended.

Choroid plexus carcinoma

Choroid plexus carcinoma is an uncommon neoplasm of the central nervous system most commonly found in the pediatric population. It is associated with a dismal prognosis, especially if incompletely resected. Accurate histopathologic diagnosis is imperative, and this neoplasm should always be included in the differential diagnosis of a papillary intraventricular tumor. Histopathologic features include blurring of papillary architecture, layers of neoplastic choroid plexus epithelial cells with pleomorphic nuclei, increased nuclear-to-cytoplasmic ratio, increased mitotic activity, areas of necrosis, and brain invasion. Current accepted treatment is gross total surgical resection of the tumor as the goal. Use of adjuvant chemotherapy is controversial at this time; however, it is considered in some cases.

[Intra-operative cytopathology: techniques, indications, and limitations]

Intraoperative cytopathology is faster, less labor intensive, yields clearer cellular details and can be as accurate as frozen section in the hands of pathologists experienced in the interpretation of cytological preparations. This procedure is particularly valuable for examining small specimens, multiple samples that need to be examined rapidly, and when superior cytological details are required. Nonetheless its use seems to be relatively limited. In this article, we review the general requirements for intraoperative cytology and also detail its value, as well as its limitations and pitfalls.