Analysis of Histomorphologic/Molecular Association and Immune Checkpoint Regulators in Epithelioid Glioblastoma and Pleomorphic Xanthoastrocytoma: Are These Tumors Potential Candidates for Immune Checkpoint Blockade?

Accurate diagnosis of Epithelioid glioblastoma (eGB) and pleomorphic xanthoastrocytoma (PXA) is sometimes challenging owing to overlapping histologic and genetic features. There are limited reports on the immune profile of these tumors. In this study, we assessed 21 PXA [15 PXA Grade 2 (PXAG2); 6 PXA Grade 3 (PXAG3)] and 14 eGB for their histopathological and molecular association. Further, their immune profile was compared with GB, IDH1 wild-type (wt) (n-18). Morphologically, PXAG2 mostly differed from eGB; however, it was occasionally difficult to differentiate PXAG3 from eGB due to their epithelioid pattern and less obvious degenerative features. PXAG2 showed predominantly diffuse, whereas variable positivity for epithelial and glial markers was seen in PXAG3 and eGB. All cases showed retained nuclear ATRX and INI-1 . H3K27M or IDH1 mutation was seen in none. P53 mutation was more common in eGB, followed by PXAG3, and least common in PXAG2. BRAF V600E mutation was observed in 66.67% PXAG2, 33.33% PXAG3, and 50% eGB, with 100% concordance between immunohistochemistry (IHC) and sequencing. Thirty-six percent eGB, 33% PXAG3, and 61% PXAG2 harbored CDKN2A homozygous deletion. EGFR amplification was observed in 14% eGB and 66% of GB, IDH wt. PDL1 and CTLA-4 expression was higher in eGB (71.4% and 57.1%), PXAG3 (66.6% and100%), and PXAG2 (60% & 66.7%) as compared with GB, IDH wt (38.8% and 16.7%). Tumor-infiltrating lymphocytes were also observed in a majority of eGB and PXA (90% to 100%) in contrast to GB, IDH wt (66%). This analysis highlights the homogenous molecular and immune profile of eGB and PXA, suggesting the possibility that histologically and molecularly, these two entities represent 2 ends of a continuous spectrum with PXAG3 lying in between. Higher upregulation of PDL1, CTLA-4, and increased tumor infiltrating lymphocytes in these tumors as compared with GB, IDH wt suggests potential candidature for immunotherapy.

Primary Dural Non-Hodgkin's Lymphoma as a Diagnostic Pitfall: Report of a Rare Presentation with Review of Literature.

Primary central nervous system lymphomas (PCNSLs) account for 2%-3% of all primary brain tumors. Lymphomas arising from the dura, without brain and other systemic involvement, constitute a tiny fraction of this rare group. Most dural lymphomas present as dural-based masses and an acute presentation as a subdural hematoma is exceptional, with only five such cases reported previously in the literature. We present the case of a 65-year-old female who was admitted with complaints of slurring of speech, visual disturbances, and reduced appetite for 2 days. Computerized tomography scan showed a crescentic hyperdense area in the left fronto-temporo-parietal region with no bony or extracranial involvement suggestive of acute subdural hematoma. There was a history of a similar episode 3 months back, wherein she was operated upon and followed up conservatively. Craniotomy for drainage was performed, and histopathology revealed a non-Hodgkin's Lymphoma. Primary lymphoma of the dura is a rare subtype of PCNSL. This case is being reported for its unusual presentation as a common entity-an acute subdural hematoma.

Multiple Primary Bilateral Cerebral Echinococcosis in an Adult: A Neurological Rarity.

Although cases of intracranial hydatid cysts are commonly encountered, majority of them are secondary and are seen in children. Primary bilateral multiple intracranial hydatid cysts in adults are a neurological rarity. Intracranial involvement usually occurs following infestation of the other organs in the body by the pathogen. Multiple lesions in brain can manifest either following rupture of a single parent cyst in brain or by systemic dissemination from other organs. Here, we are presenting an adult patient who underwent successful surgical removal of multiple primary hydatid cysts of brain. A 47-year-old male patient presented with features of raised intracranial pressure and other focal deficits. Magnetic resonance imaging showed multiple cystic lesions on both sides of the cerebrum. Similar primary lesions elsewhere in the body were ruled out by other investigations. He underwent successful surgical removal of all the lesions. Intraoperative picture and histology were suggestive of hydatid cyst. In published literature, there are very few cases similar to ours. Echinococcosis should be considered as a differential diagnosis in multiple cystic lesions of the brain in endemic areas. Early diagnosis, proper surgical technique, and standard antihelminthic drug regimen are the key to achieve good outcome in these patients.

Extra-axial adult cerebellopontine angle medulloblastoma: Revisiting a rare entity.

A purely extra-axial position of medulloblastoma in adults at cerebellopontine (CP) angle is extremely rare. To the best of our knowledge, only ten cases have been reported till date. The authors report a case of extra-axial medulloblastoma in a 30-year-old female located at right CP angle. It was surgically treated with a provisional diagnosis of meningioma. Histopathological diagnosis of desmoplastic/nodular medulloblastoma was made with the routine hematoxylin eosin (HE) stain and immunohistochemical markers. This case report highlights the fact that, although extremely rare, the possibility of an extra-axial CP angle mass being a medulloblastoma still needs to be considered in the differential diagnoses, even in adults.

Gene expression based profiling of pleomorphic xanthoastrocytoma highlights two prognostic subgroups.

BACKGROUND: Pleomorphic xanthoastrocytomas (PXAs) are rare, accounting for less than 1% of astrocytomas, and commonly occur in young patients. The majority are WHO grade II. A fraction of tumors that present or recur with malignant change are classified as anaplastic (APXA, grade III). Limited data are available on their molecular characteristics. METHODOLOGY: Genome-wide expression profiling of 14 PXA and 6 APXAs was performed by microarray. Among differentially expressed genes (DEGs), Cyclin-Dependent Kinase 14 (CDK14) and Mitochondrial Fission Process 1 (MTFP1) were validated by qRT PCR. RESULT: Unsupervised hierarchical clustering revealed two distinct molecular clusters (Cluster 1: 10 PXA, 3 APXA and Cluster 2: 4 PXA, 3 APXA) with grade II and III tumors distributed in both highlighting molecular heterogeneity within the same grade. There was an insignificant difference in age, sex, immunohistochemical profile, frequency of BRAF mutation, or CDKN2A deletion among the two clusters. Significantly, worse progression-free survival was observed in cluster 2 (P=0.003). mRNA profiling-based prediction of recurrence was superior to and independent of histological grade, BRAF mutation, or CDKN2A deletion status. A total of 10 upregulated and 418 downregulated genes were identified between the PXA clusters. qRT-PCR validation of CDK14 (upregulated in cluster 2) and MTFP1 (upregulated in cluster 1) showed strong concordance with expression array data. CONCLUSION: This is the first comprehensive study highlighting distinct molecular subgroups of PXA. The differentially expressed genes between two clusters may potentially be used for developing histology independent classification schemes, prognostication and may serve as prospective therapeutic targets for PXA patients.

Gangliocytic paraganglioma of the spine.

Paragangliomas are rare, encapsulated, benign neuroendocrine tumors that can arise from the adrenal medulla or extra-adrenal paraganglia. Extra-adrenal paragangliomas may develop a gangliocytic component with ganglion cells (Gangliocytic paragangliomas). Nearly 25%of cauda equina paragangliomas are gangliocytic paragangliomas. Here, we describe the case of a 35-year-old male who presented with weakness of both lower limbs over the last two months. Radiological findings were suggestive of myxopapillary ependymoma. However, the histopathological examination revealed a tumor with cells arranged in sheets, papillae, lobules, and around vessels forming pseudo rosettes. Ganglion cells were seen in small groups and, also singly. Tumor cells were immunopositive for chromogranin, synaptophysin, and S-100. Ganglion cells were immunopositive for synaptophysin, NSE, and NFP. A final histological diagnosis of Gangliocytic paraganglioma (WHO grade I) was made. To date, only nine gangliocytic paraganglioma cases have been previously reported, and to the best of our knowledge, this is the largest gangliocytic paraganglioma.

Historadiological Correlation of Cerebellopontine Angle Tumors: Series of 122 Cases.

Cerebellopontine angle (CPA) tumours, are diverse pathologically with regard to the site of tumour origin and displacement of the neurovascular structures. In general CPA tumours are divided into acoustic and non-acoustic tumours. The aim of the present study was to see the spectrum of lesions at cerebellopontine angle and their historadiological correlation. A retrospective analysis of 122 cases of CPA tumors diagnosed in the Department of Pathology, IHBAS was done from January 2004 to August 2019. There were 56 males and 66 females in the age group of 8-68 years. Clinical history ranged from 10 days to 5 years. Clinical symptoms included hearing deficit, visual loss, facial nerve dysfunction, nausea, vomiting, headache, seizures, unsteadiness and disequilibrium. Historadiological correlation was found in 112 cases (91%).In our series of CPA tumors, nonacoustic tumors were more frequent than in previous studies. We found that presence of intrameatal fraction is not exclusive only for schwannomas. There can be a rare occurrence of medullobastoma/small round cell tumor in CP angle. The final pathological verification can at times give unexpected results. Immunohistochemistry did not have a significant role in diagnosis of cerebellopontine angle tumors.

Gangliocytic paraganglioma of the spine

Paragangliomas are rare, encapsulated, benign neuroendocrine tumors that can arise from the adrenal medulla or extra-adrenal paraganglia. Extra-adrenal paragangliomas may develop a gangliocytic component with ganglion cells (Gangliocytic paragangliomas). Nearly 25%of cauda equina paragangliomas are gangliocytic paragangliomas. Here, we describe the case of a 35-year-old male who presented with weakness of both lower limbs over the last two months. Radiological findings were suggestive of myxopapillary ependymoma. However, the histopathological examination revealed a tumor with cells arranged in sheets, papillae, lobules, and around vessels forming pseudo rosettes. Ganglion cells were seen in small groups and, also singly. Tumor cells were immunopositive for chromogranin, synaptophysin, and S-100. Ganglion cells were immunopositive for synaptophysin, NSE, and NFP. A final histological diagnosis of Gangliocytic paraganglioma (WHO grade I) was made. To date, only nine gangliocytic paraganglioma cases have been previously reported, and to the best of our knowledge, this is the largest gangliocytic paraganglioma.

Revisiting metastatic central nervous system tumors with unknown primary using clinicopathological findings: A single neurosciences institutional study.

BACKGROUND: Metastatic tumors are the most common central nervous system (CNS) tumors wherein the primary site remains unknown in most of the cases. Aim: The study was carried out to evaluate metastatic CNS tumors with unknown primary by using simplified diagnostic (clinico-histopathologic) approach. MATERIAL AND METHODS: A 2 years study was conducted on 32 cases of CNS metastases having unknown primary tumors in a neurosciences institute. STATISTICAL ANALYSIS: All the results were prepared using software version of SPSS 22. RESULTS: The most common metastatic site found in brain was cerebrum (59.3%) [frontal > frontoparietal > parieto-occipital > temporal] [left cerebrum > right cerebrum], followed by cerebellum (12.5%), spinal cord (9.3%), and leptomeninges (3.12%). Most of the metastatic tumors presented as ill-defined (34%) rather than well-defined (22%) lesions with ring enhancement seen only in 16% of the cases on magnetic resonance imaging (MRI).On histopathology findings with targeted immunohistochemistry, most common histological tumor type identified irrespective of site was adenocarcinoma (68.7%), followed by squamous cell carcinoma (15.6%) and poorly differentiated carcinoma (12.5%). Only one case of lymphoma was reported. Corroborating all the above findings along with clinical history and other relevant investigations, primary sites could be detected in 23 cases (71.8%).The most common primary site deduced was lungs (39.1%), followed by thyroid (17.3%), breast in females (13.0%), gastrointestinal tract (8.6%), and prostate in males (4.3%). Only in nine cases (28.1%) with mainly poorly differentiated histopathological type, primary site remained unknown. CONCLUSION: Detection of the primary site in metastatic CNS tumors is possible by adopting this simple and effective diagnostic approach at centers/hospitals having cost and other constraints.

A rare case of diffuse intracranial aspergillosis masquerading as skull base meningioma in an immunocompetent patient.

Intracranial aspergillosis is rare in immunocompetent patients. Its presentation is subtle, often without any diagnostic characteristics, and is frequently mistaken for tuberculous meningitis, pyogenic abscess, or a space-occupying lesion. The authors report a case of diffuse intracranial aspergillosis, in an immunocompetent 34-year-old male, that mimicked a meningioma on preoperative imaging. The origin, clinical course, radiological features, histopathological findings, and surgical treatment are discussed based on review of literature.
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Intramedullary schwannoma of conus medullaris: rare site for a common tumor with review of literature.

INTRODUCTION: Schwannomas at an intramedullary location constitute only 0.3% of primary spinal tumors. Those in the conus are extremely rare, especially in the absence of neurofibromatosis, with only 12 cases reported in the literature so far, excluding the present case. CASE PRESENTATION: We report the case of a 27-year-old female who presented with complaints of backache since 1 year, weakness in both lower limbs with tingling and numbness since 6 months, and urinary incontinence since 1 month. There was no history of trauma or any skin lesions. Magnetic resonance imaging (MRI) of the spine provided a provisional diagnosis of ependymoma. The patient was operated upon, histopathology revealed it to be a schwannoma. DISCUSSION: Intramedullary schwannomas without neurofibromatosis are extremely rare at the conus and can be completely resected unless there is infiltration. Gliomas and ependymomas are commoner entities at this site, which are usually subtotally resected. This case highlights that although extremely rare, the possibility of a schwannoma may be considered in the differentials of an intramedullary spinal lesion.

Congenital Skull Anomaly with Multiple Brain Stones and Symptomatic Meningioma of Medial Sphenoid Wing.

Intracranial calcifications are not uncommon and are mostly seen with intracerebral hematomas, tuberculomas, and brain tumors. These lesions may be intra- or extra-axial and occasionally pose challenge in the diagnosis. We report a case of multiple intracranial extra-axial calcifications with congenital skull anomaly and multiple meningiomas. Authors could not find similar case reported in the literature and present their findings and discuss relevant literature.

Peripheral neuropathy and the role of nerve biopsy: A revisit.

BACKGROUND: Nerve biopsy has been widely used to investigate patients with peripheral neuropathy and in many centers, it is still a part of the diagnostic armamentarium. In this study, the histopathological spectrum of the nerve biopsies received is being revisited to analyze the various clinical and pathologic features and also to assess their relevance. MATERIALS AND METHODS: Retrospective analysis of the data retrieved was done for 74 cases of nerve biopsies. RESULTS: On the basis of the data and histopathological features, broad diagnoses were obtained in 52 cases and further categorized into biopsies being supportive for patient management (including acute and chronic axonopathies and demyelinating neuropathies) and biopsies considered essential for patient management (including vasculitic neuropathies, leprous neuropathies, hereditary neuropathies, and chronic inflammatory demyelinating neuropathies). Nine nerve biopsies did not show any abnormal histopathological features, while 13 nerve biopsies were found to be inadequate for diagnosis, both these groups were categorized as noncontributory. CONCLUSION: With advanced nerve conduction studies available, nerve biopsy is losing its relevance. However, in our experience, nerve biopsy did complement the clinical findings and nerve conduction studies, with which a close correlation is required to make the histopathology of nerve biopsy more relevant in terms of guiding further specific workup and management.

Immunohistochemical and molecular genetic study on epithelioid glioblastoma: Series of seven cases with review of literature.

Epithelioid glioblastoma (e-gbm) is a recently described variant of glioblastoma (GBM) which is associated with short survival and now added as a provisional entity to WHO 2016 classification of CNStumors. About half of these tumors show characteristic BRAF-V600E mutation. However, unlike conventional GBMs, e-gbm lack specific diagnostic and prognostic markers. Hence, we aimed to molecularly characterize these tumors. An extensive review of literature was performed.In a multi-institutional effort, all the cases of glioblastoma of year 2017 were reviewed. Cases with predominant epithelioid morphology were analysed. Seven cases of e-gbm (adults:4 and pediatric: 3) were identified. Duration of symptoms varied from 2 weeks to one month. Radiologically, all cases were supratentorial, contrast enhancing with solid and cystic appearance. Majority of the cases were immunopositive for GFAP (71%), EMA (71%), S100 (71%) and vimentin (85%). All the cases showed ATRX, INI-1 and H3K27me3 expression. BRAFV600Emutation was seen in 28% of cases. TERT mutation was seen in 40% cases, while one case showed EGFR amplification. H3F3A mutations and PTEN deletions were seen in none. Although e-gbms are rare, epithelioid morphology of a CNS tumor in a young adult or children with areas of necrosis needs thorough histomorphological and genetic workup.

Giant Cell Glioblastoma in a Child with Clinical and Family History of Neurofibromatosis.

We report a case of giant cell glioblastoma (GCG) in a 13-year-old child with clinical features and family history of neurofibromatosis type 1 (NF1). To the best of our knowledge, only two cases of GCG have been reported in a scenario of NF1, and only one of that was in a pediatric age group. A report on our case is presented here along with a review of literature.

Spinal tumour: primary cervical extradural meningioma at an unusual location.

Extradural spinal meningiomas are extremely rare, more so in the cervical region. A purely extradural location as reported in this paper is quite exceptional. The authors report a case of extradural meningioma in a 50-year-old male located in the cervical spine that was surgically treated with the provisional diagnosis of a neurofibroma. Histopathological diagnosis of meningothelial meningioma was made with the routine hematoxylin and eosin (HE) stain. The origin, clinical course, radiological features, pathological findings with the differential diagnosis and surgical treatment are discussed based on a review of the literature. An extradural spinal meningioma, an extremely rare entity, is still a diagnostic dilemma on radiology as the radiologic findings overlap with many other common extradural spinal masses.