Rapid malignant transformation of an intracranial epidermoid cyst: Report of a case.

Intracranial epidermoid cysts (ECs) occur at various locations along the neuraxis and account for nearly 2% of all intracranial tumors. Considering the frequency of ECs, transformation of ECs into squamous cell carcinomas is a rare occurrence. Here, we report the case of a 39-year-old man who presented with a lesion in the left cerebellopontine angle and underwent gross total resection for the same. Histopathological examination revealed a benign EC with mild chronic inflammation. Five months later, the patient presented with another lesion at the same location with evidence of brainstem bleed. Histopathological examination revealed a moderately differentiated squamous cell carcinoma and remnants of the previous cyst in the form of lamellated keratin, indicating malignant transformation of the EC.

Nonneoplastic and noninfective cysts of the central nervous system: A histopathological study.

Nonneoplastic epithelial cysts involving the central nervous system are diverse and are predominantly developmental in origin. This study represents a surgical series describing the histopathological features of 507 such epithelial cysts with clinical and imaging correlation. Age at surgery ranged from 7 months to 72 years (mean: 33 years) affecting 246 male and 261 female patients. Colloid cyst was the most frequently resected cyst, followed by epidermoid cyst, arachnoid cyst, Rathke cleft cyst, dermoid cyst, neurenteric cyst, Tarlov cyst, and choroid plexus cyst. Diagnosis was based on the location of the cysts and the nature of the lining epithelium. Rathke cleft cyst showed the highest propensity for squamous metaplasia, significant inflammation, and xanthogranulomatous reaction. Ulceration of lining epithelium and calcification were most frequent in dermoid cyst. Radiopathological concordance was maximal for colloid cyst, followed by epidermoid and arachnoid cysts. Epidermoid and dermoid cysts exhibited the highest propensity for local tumor progression, followed by Rathke cleft cyst.

Atypical teratoid rhabdoid tumour in the third ventricle of a young adult - a rare presentation.

INTRODUCTION: Atypical teratoid/rhabdoid tumours (AT/RT) are malignant CNS tumours predominantly seen in infants and children. Adult AT/RTs have a predilection for mid-line structures, such as the pineal and pituitary glands. We report a case of AT/RT in a young adult, with its origin from the third ventricle. This is the first documented case of adult AT/RT in the third ventricle. CASE PRESENTATION: A 20-year-old male presented with acute onset headache and vomiting. MRI showed a lesion involving the optic chiasm, hypointense on T1, and heterogeneously hyperintense on T2, with stippled post-contrast enhancement. He underwent a right peri-coronal parasagittal craniotomy, transforaminal and sub choroidal approach with gross total tumour resection. Histopathological report was ATRT, WHO grade 4, with loss of SMARCB1 (INI1) protein. He later underwent a ventriculo-peritoneal shunt placement for postoperative hydrocephalus and was later given adjuvant chemoradiotherapy. No recurrence was noted on follow up MRI. CONCLUSION: AT/RTs are not limited to the paediatric age group, and their incidence among adults is being increasingly reported. Occurrence of AT/RT in the third ventricle of a young adult male has never been reported in the past. It merits consideration as a differential diagnosis of any midline lesion with malignant appearance in adults.

Cyanosis and Clipping: Noninfectious Aneurysm in a Patient with 22q11.2 Deletion Syndrome.

Noninfectious cerebral aneurysms are rare in patients with congenital cyanotic heart disease. We present a patient with DiGeorge/velocardiofacial syndrome with a complex congenital cyanotic heart disease with a ruptured anterior communicating artery aneurysm. The 10-year-old child was managed by surgical clipping of the aneurysm. Surgical challenges included prominent veins in the Sylvian fissure, difficulty in differentiating arterial and venous bleed, and anesthetic risks. The patient recovered without any neurological deficits. This is the first report of a patient with 22q11.2 deletion syndrome, with a noninfectious cerebral aneurysm.

Meningioma with rosettes: A rare morphologic pattern.

We describe a case of WHO grade I transitional meningioma with rosettes in a 68-year-old woman. The rosettes were composed of meningothelial cells arranged around dense collagenous cores. Even though the presence of rosettes in tumors of the brain and spinal cord is an indication of neuronal or ependymal differentiation, they are also known to occur in tumors of other lineages. Rosette is an uncommon morphological pattern in meningiomas, with only few cases reported in the literature.

Haemosiderin cap sign in cervical intramedullary schwannoma mimicking ependymoma: how to differentiate?

A 37-year-old female presented with gradually progressive asymmetric ascending paraesthesia and weakness involving bilateral upper and lower limbs. The MRI spine images revealed expansile intramedullary, solid cystic, peripherally enhancing lesion with a haemosiderin cap along the lower margin. The lesion extended into the left C5 and C6 nerve root exit zones, along with thickening and enhancement of the nerve roots. She underwent excision of the lesion, which revealed intramedullary schwannoma on histopathological examination. Presence of the cap, an extension of the lesion into the nerve root exit zone, with associated thickening and enhancement of the dorsal nerve roots should alert the radiologist to consider the possibility of intramedullary schwannoma rather than ependymoma. Schwannoma showing compact Antoni A area with Schwannian whorls and nuclear palisades (A,B) and loose Antoni B area with haemosiderin pigment (C). The tumour exhibits diffuse positivity for S-100 protein (D) and negativity for GFAP (E). [Stain: A-C: Haematoxylin and Eosin; D,E: Immunoperoxidase. Magnification = Scale Bar, A-E: 100µm].

Chordoid meningioma: a clinico-pathological study of an uncommon variant of meningioma.

Chordoid meningioma is a rare variant of meningioma, with a higher incidence in the young and a supposed association with Castleman's syndrome. They have an aggressive clinical course, and are assigned as WHO grade II meningiomas. To the best of our knowledge, 284 chordoid meningiomas have been reported in the literature. This series reporting 33 cases is the third largest series in published literature from a single Institution. We reviewed Clinico-pathological characteristics of 33 patients diagnosed with chordoid meningioma between 2001 and 2015 in our institution. Forty-one specimens were available for review of histopathological and immunohistochemical characteristics. There were 15 men and 18 women with mean age of 36.8 years (median 36 years, range 9-62 years) at diagnosis with three cases occurring in pediatric age group. The majority were supratentorial in location with 11 convexity, 1 falcine, 5 parasagittal, 1 intraventricular, skull base involvement in 12 with 4 being petroclival location and 3 had spinal lesions. Lymphoplasmacytic infiltrates were seen in 23 cases with majority being T cells. MIB index varied from 1 to 14%. Five patients received radiotherapy for residual lesion. Two patients died (recurrence-1, post-operative complication-1). Three patients were lost to follow up after surgery. The mean post-operative follow up period for the remaining was 55.3 months. Seven patients had recurrence of which three had it twice. This study adds to the pool of available data for better understanding of this variant of meningioma. These meningiomas occur in middle age; spinal lesions and pediatric cases are not uncommon. We did not find any association between surgery, post-operative radiotherapy and histopathological features with recurrence and survival. Small number of cases may be responsible for this statistical insignificance.

Intraventricular gliosarcoma with dual sarcomatous differentiation: A unique case.

Gliosarcoma, a variant of isocitrate dehydrogenase-wildtype glioblastoma, is largely a lobar surfacing neoplasm often with dural attachment. In this biphasic neoplasm, the sarcomatous component usually takes the form of fibrosarcoma or malignant fibrous histiocytoma. Heterologous sarcomatous differentiation is a rare phenomenon. Here, we present a case of gliosarcoma with liposarcomatous and myosarcomatous differentiation in a 68-year-old man which was purely intraventricular. This is the first report of such a morphologic pattern in this location. Varied histological components with their immunohistochemical profile are discussed. Of note was the presence of a p53 negative giant cell glioblastoma component, as was the expression in the rest of the tumor.

Femoral Vein Intravascular Synovial Sarcoma Mimicking Primary Deep Vein Thrombosis-A Rare Cause of Deep Vein Thrombosis.

Synovial sarcomas are rare malignant mesenchymal soft tissue tumors. We presented the case of a 53-year-old woman patient presenting with acute deep vein thrombosis, later diagnosed as a deep synovial sarcoma of the femoral vein wall. The tumor was identified through cross-sectional magnetic resonance angiography and computed tomography, followed by ultrasound-guided core biopsy. The case report emphasized the importance of considering the possibility of an intravascular neoplasm mimicking thrombus, particularly if calcifications, vein expansion with intravascular cystic spaces, fluid-fluid levels, and septations within a thrombosed vein are seen in imaging.

Thrombus histology does not predict stroke etiological subtype but influences recanalization.

BACKGROUND: There is conflicting data on whether clot retrieved from mechanical thrombectomy can predict stroke etiology or the success of recanalization. We aimed to analyse the relation between thrombus histology and stroke aetiology as well as recanalization. METHODOLOGY: Histopathological analysis of clots retrieved from patients with acute ischemic stroke and large vessel occlusion was done. Quantification of the amount of fibrin, red blood cells(RBC), platelets and white blood cells (WBC) in the clots were done. The clinical, imaging data and recanalization parameters were collected. The correlation between clot composition and stroke etiology as well as recanalization were analysed. RESULTS: Of the 77 patients, the mean age was 58. 67 ± 12.96 years. The stroke etiology were cardioembolism 44(57.1 %), large artery atherosclerosis 13(16.8 %), other determined aetiology 4(5.1 %) and undetermined in 16(20.7 %) patients. There was no significant correlation between the proportions of RBC-rich, platelet-rich and fibrin-rich thrombi and the stroke etiology. The susceptibility vessel sign was associated with RBC-rich clot(92.3 % vs 7.7 %, p = .03). All RBC-rich clots(100 %) had good recanalization(p = .05). Platelet-rich clots needed less number of passes(64.7 % vs 35.3 %, p = .006) and reduced groin puncture to recanalization time(87.9 % vs 12.1 %, p = .033). WBC-rich clots required lesser number of passes(57.5 % vs 42.5 %, P = .044). In multivariate analysis, WBC-rich clots (OR 0.230, CI 0.07-0.78, p = .018) showed an independent association with reduced recanalization attempts, while platelet-rich clots showed reduced recanalization time(OR 0.09, CI 0.01-0.63, p = .016). CONCLUSION: There was no correlation between thrombus histology and the etiological stroke subtype. However, clot composition predicted the degree of recanalization and number of passes.

Clinical Reasoning: A Teenager With Chronic Meningitis-Does Occam's Razor Apply?

A 14-year-old girl presented with subacute onset headache, fever, and vomiting and was managed initially with antibiotics for suspected bacterial meningitis. Her symptoms further evolved over the next few weeks with systemic signs and symptoms favoring chronic meningitis with raised intracranial pressure. After the etiologic workup was unrevealing, she was started on empirical antituberculous therapy. After a period of partial improvement, symptoms recurred with a new-onset focal seizure. Her imaging findings evolved from features suggestive of focal leptomeningitis to multifocal heterogeneous enhancing cortical and subcortical lesions with hemorrhagic foci, leading to brain biopsy that confirmed diagnosis. Our case highlights the utility of diagnostic biopsy in patients with "chronic meningitis" in uncertain cases rather than confining the approach to the law of parsimony. The decision to initiate empirical therapy in chronic meningitis should be considered on a case-by-case basis and take into account factors, such as clinical examination findings, immune status, recent exposures, and potential risks of treatment. Atypical MRI features should lower the threshold for meningocortical biopsy when indicated.

Pathology of surgically remediable epilepsy: How to evaluate.

Epilepsy surgery is a well-established treatment modality in selected cases of medically refractory epilepsy. Advances in neuroimaging technology has greatly facilitated detection of lesions that are surgically amenable. Hippocampal sclerosis is the most common pathology encountered among specimens from epilepsy-related surgeries. Other common pathologies are malformations of cortical development including focal cortical dysplasia, neoplasms, vascular malformations, inflammatory conditions including Rasmussen encephalitis and glial scars. Proper handling of surgical specimens is necessary for microscopic evaluation. Accurate interpretation and classification of lesions will help define clinically relevant etiologies. In this review, neuropathological aspects of the common etiologies underlying drug-resistant epilepsies are discussed.

Mosaic Pattern of H3 K27M-Mutant Protein Expression in a Diffuse Midline Glioma-A Diagnostic Dilemma for the Pathologist.

Diffuse midline glioma, H3 K27M-mutant, is a World Health Organization (WHO) grade IV glioma arising in pons, thalamus, and spinal cord. They show mutations resulting in replacement of lysine at position 27 by methionine (K27M) of histone genes, H3F3A , HIST1H3B, and HIST1H3C. The H3 K27M mutant protein is identified in tumor tissue by immunohistochemistry. As these mutations are clonal and homogeneous, the mutant protein is normally identified in all tumor cells. Here we report a case of diffuse midline glioma with mosaic pattern of expression of H3 K27M mutant protein and discuss the diagnostic and therapeutic implications of this unusual pattern.

Glioblastoma with primitive neuronal component: An immunohistochemical study and review of literature.

Glioblastoma with primitive neuronal component, a rare neoplasm, is recognized as a distinct histological pattern of glioblastoma. In this study we report the morphological and immunohistochemical features of three cases of glioblastoma with primitive neuronal component diagnosed at the Institute along with a comprehensive literature review. The cases include: (1) 11-year-old girl with right fronto-parietal lesion, (2) 48-year-old male with right parietal lesion, and (3) 36-year-old male with left fronto-parietal lesion. Case 1 had prior history of glioblastoma. All the cases had classic morphology of glioblastoma along with GFAP-negative and synaptophysin-positive primitive neuronal component. The latter was poorly demarcated from the glial component in case 1, while well-defined in the remaining two. All the three cases exhibited diffuse p53 positivity and a higher MIB-1 labelling index in the neuronal component compared to the glial component. One of them (case 3) was IDH1 R132H-mutant with loss of ATRX expression. None were positive for K27M-mutant H3 or G34R-mutant H3.3. Literature review of 50 published cases of glioblastoma with primitive neuronal component was performed. The age of onset ranged from 3 months to 82 years (mean: 50 years) with M:F of 1.5:1. 18.8% of tumors were IDH-mutant, 87.5% were p53 positive and three cases showed H3F3A gene mutations. There was a greater propensity for neuraxial dissemination, noted in 20% of cases. Overall survival of glioblastoma with primitive neuronal component was similar to that of IDH-wildtype glioblastoma (13 months) which was significantly shorter compared to the overall survival of IDH-mutant glioblastoma (33.6 months).

Simultaneous trigonal and spinal meningioma with varied histology: A rare case report.

BACKGROUND: Meningioma is one of the most common neoplasms of the central nervous system. Multiple meningiomas without neurofibromatosis are not a usual occurrence. Intraventricular meningioma with spinal meningioma is rare and not been reported in the literature. CASE DESCRIPTION: We report a case of a 63-year-old male with the left trigonal and spinal meningioma. Both the meningiomas were resected in different settings. The histological examination of tumors revealed to be of varied histology, that is, meningothelial and atypical meningioma, respectively. CONCLUSION: Although various cases with multiple cranial and spinal meningiomas are described, this is the first case of an intraventricular and spinal meningioma. With varied histology, the case also reaffirms the theory of polyclonal origin of multiple meningiomas.

Pericardial pseudocyst along atrioventricular groove.

Cystic lesions in relation to the pericardium are a rare congenital lesion with an estimated incidence of 1 per 100,,000. Pericardial cysts may be classified as congenital or acquired. Here, we present a case of a pericardial pseudocyst having a horseshoe configuration along the atrioventricular groove in a middle-aged subject with no previous relevant medical history. The patient underwent open surgery for the same with histopathological diagnosis being established. This paper highlights the differentials for a cystic pericardial lesion in imaging in addition to the histopathological entity of a pericardial pseudocyst.

Neuropathological spectrum of drug resistant epilepsy: 15-years-experience from a tertiary care centre.

Neuropathology of drug resistant epilepsy (DRE) has direct bearing on the clinical outcome. Classification of the most common pathologies, hippocampal sclerosis (HS) and focal cortical dysplasia (FCD) have undergone several revisions and studies on the surgical pathology of DRE employing the updated ILAE classification are scarce. Here, we report the neuropathological spectrum of 482 surgically treated cases of DRE from a single institute using the latest ILAE classifications along with clinicoradiologic correlation. Majority of the cases (324, 67.2%) had temporal lobe epilepsy (TLE), with 158 (32.8%) having extratemporal seizure focus. Among TLE, HS was most common (n = 208, 64.2%), followed by neoplasms (42, 13%), FCD (26, 8%) and dual pathology (23, 7%). Less frequent were vascular malformations (cavernoma-3, arteriovenous malformation-1), mild malformation of cortical development (mMCD, 3), gliotic lesions (5), cysticercosis (2), double pathology (2) and polymicrogyria (1). Among extratemporal epilepsies, FCD was most common (46, 29.1%), followed by neoplasms (29, 18.3%), gliotic lesions (27, 17.1%), Rasmussen encephalitis (18, 11.4%), hypothalamic hamartoma (12, 7.6%), malformations of cortical development (10, 6.3%) and vascular malformations (6, 3.8%). Less frequent were double pathology (2, cysticercosis + FCD type IIb, DNET + FCD type IIb), mMCD (2), cysticercosis (1) and dual pathology (1). No underlying pathology was detected in 12 cases (2.5%). Radiopathological concordance was noted in 83%. In 36 cases (7.5%), histopathology detected an unsuspected second pathology that included FCD type III (n = 16) dual pathology (n = 18) and double pathology (n = 2). Further, in four MRI negative cases, histopathology was required for a conclusive diagnosis.

Dual/double pathology in neurocysticercosis causing drug resistant epilepsy - Chance association or causal?

INTRODUCTION: Neurocysticercosis (NCC) as cause of drug resistant epilepsy (DRE) is commonly reported from India. We reviewed the neuropathological findings in patients undergoing resective surgery for DRE due to NCC, to determine the pathomechanism of epileptogenesis. METHODS: Clinical, demographic and neuropathological findings of histologically confirmed cases of NCC causing DRE between 2005-2019 were reviewed. NeuN, GFAP, phosphorylated neurofilament, vimentin, CD34 for glial/ neuronal alterations, and Masson trichrome, Luxol Fast blue for evidence of fibrosis/ demyelination was used to determine cause of epileptogenesis. RESULTS: There were 12 cases of NCC associated with dual/ double pathology, which constituted 3.02 % (12/398) of all the operated DRE. [Age range: 17-37y, Male:Female = 1.4:1]. Seizure duration ranged from 3-32y, with seizure onset between 4-27y. On MRI, lesions were of variable signal intensity on T1 and isointense on T2 with blooming on GRE/ SWI, and CT revealed calcification. Majority (11/12) had associated hippocampal sclerosis (HS) type 1 (dual pathology), localised to the same side as cysticercal cyst, suggesting it may be involved in the pathogenesis of HS. Ten had single cysticercal lesion involving ipsilateral hippocampus in 6, parahippocampal gyrus in 2, amygdala and temporal lobe in 1 case each. One had multiple NCC located in bilateral frontal, parietal and ipsilateral hippocampus. Adjacent cortex around the NCC evaluated in 6 cases, revealed inflammation, gliosis, axonal disruption/ beading, and variable synaptic/ neuronal dystrophic changes. There was a single case of NCC with Focal cortical dysplasia (FCD) type IIb (double pathology). In 11/12 cases Engel's post-surgery outcome was available with all having class I outcome. CONCLUSION: HS was most common pathology associated with cysticercosis (Dual pathology), localised ipsilateral to the cysticercal cyst, suggesting that HS is a secondary/ epiphenomenon. Perilesional changes such as inflammation, gliosis, dystrophic synaptic and axonal pathology play a role in inducing or perpetuating the epileptiform activity. The association of FCD IIb with NCC in one case is likely to be a chance occurrence.

An unusual presentation of scleromyxedema as inflammatory myopathy.

Scleromyxedema is a rare cutaneous mucinosis with frequent extracutaneous manifestations. Myopathy in scleromyxedema is a poorly recognized syndrome among neurologists and can mimic idiopathic and connective tissue disease-associated inflammatory myopathy. Diagnosis is suspected by the characterization of the skin lesions and clinched by skin and muscle biopsies. Here, we report a patient with scleromyxedema and myopathy with the characteristic histopathological feature of mucin deposition in skin biopsy. Her muscle biopsy showed a picture consistent with scleromyxedema myopathy with vacuolar and inflammatory changes. The association with paraproteinemia, propensity to life-threatening central nervous system disease and good response to intravenous immunoglobulin necessitate the accurate diagnosis of this condition.