Imaging of central nervous system emergencies in oncology.

Central nervous system (CNS) may be predisposed to devastating complications in cancer patients which may add to morbidity and mortality in this group. Majority of the complications are vascular in nature due to the altered coagulation profile and pro-inflammatory state in these patients. However, there are a host of other conditions which may affect the clinical course of these patients including metabolic and toxic encephalopathies, infections, and paraneoplastic syndromes. Moreover, multimodality management of these patients, which is often used in majority of the cancers, exposes them to treatment related complications. This pictorial review aims to enlighten the reader regarding the various complications affecting the CNS as seen at our tertiary cancer care institute. We aim to highlight the emergent nature of these complications and the need to identify them quickly and accurately on imaging which helps to institute early appropriate management and prevents further morbidity and mortality.

Persistent Primitive Olfactory Artery: Three Cases.

ABSTRACT: The persistent primitive olfactory artery is a very rare arterial variant with a little over a score of cases reported in literature so far. We present 3 cases illustrating this entity, which were incidentally diagnosed while imaging for other indications.

Imaging of neurovascular emergencies in pregnancy and puerperium.

Acute neurovascular events, though rare, can complicate pregnancy and postpartum period. It is important to be aware of these clinical conditions for reducing maternal and fetal morbidity and mortality. In this review, we present a few important neurovascular emergencies and their imaging manifestations by various imaging modalities-computed tomography (CT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA)-which presented at our institution in the peripartum period.

Hirayama disease/cervical flexion-induced myelopathy progressing to spastic paraparesis: A report on three cases with literature review.

Hirayama disease (HD)/cervical flexion-induced myelopathy (CFIM) is a lower motor neuron disease conventionally affecting a single upper extremity. We describe three men progressing after a long stable period to develop severe spastic paraparesis and bladder disturbances as a protracted implication of HD. The age at onset was 20, 24, and 15 years, while the age at presentation was 27, 41, and 57 years, respectively. The second phase of disease progression occurred after 4, 13, and 28 years of stationary period. All had CFIM with characteristic magnetic resonance imaging features as observed during progressive stages. The anterior dural shift extended variably from C4 to D4 levels with a median value of 5 mm and was maximum at C6 to C7 levels, pushing the cord anteriorly causing compression. This study emphasizes the need to recognize this unusual subgroup of HD and mandates long-term follow-up with timely intervention in arresting the progression/improving the deficits.

Demystifying the Mystery of Genes: A Case Report on Constitutional Mismatch Repair Deficiency.

Constitutional mismatch repair deficiency (CMMRD) is a rare childhood cancer predisposition syndrome that results from biallelic germline mutations in one of the four MMR genes, MLH1, MSH2, MSH6, or PMS2. This syndrome is characterized by a broad spectrum of early-onset malignancies, including hematologic malignancies, colorectal malignancies, brain tumors, and other malignancies. It is common to have more than one malignancy in an individual diagnosed with CMMRD. In addition to malignancies, primary immunodeficiency in the form of low or absent immunoglobulin levels can also be seen in CMMRD. Congenital abnormalities such as agenesis of the corpus callosum (ACC), cavernous hemangioma, and other non-neoplastic diseases can also be linked to it. In this case report, we discussed the case of a girl born out of consanguineous marriage initially identified as having T-cell acute lymphoblastic lymphoma and later found to have selective immunoglobulin A (IgA) deficiency. Her younger sibling with a pontine cavernous hemangioma was also diagnosed with lymphoma. The girl exhibited brain lesions on magnetic resonance imaging (MRI), which were initially diagnosed as posterior reversible encephalopathy syndrome (PRES) related changes; however, one of the lesions persisted and remained stable over a period of 2 years and more in favor of diffuse glioma. The younger sibling also showed a solitary lesion in the brain. Based on the clinical and radiological findings, a diagnosis of CMMRD was suspected. Next-generation sequence (NGS) analysis of her blood sample was done. The results showed a homozygous mutation in the MSH6 gene was diagnostic of CMMRD.

PRRT with Lu-177 DOTATATE in Treatment-Refractory Progressive Meningioma: Initial Experience from a Tertiary-Care Neuro-Oncology Center.

PURPOSE: Refractory and/or recurrent meningiomas have poor outcomes, and the treatment options are limited. Peptide receptor radionuclide therapy (PRRT) has been used in this setting with promising results. We have documented our experience of using intravenous (IV) and intra-arterial (IA) approaches of Lu-177 DOTATATE PRRT. METHODS: Eight patients with relapsed/refractory high-grade meningioma received PRRT with Lu-177 DOTATATE by IV and an IA route. At least 2 cycles were administered. Time to progression was calculated from the first PRRT session to progression. The response was assessed on MRI using RANO criteria, and visual analysis of uptake was done on Ga-68 DOTANOC PET/CT. Post-therapy dosimetry calculations for estimating the absorbed dose were performed. RESULTS: Median time to progression was 8.9 months. One patient showed disease progression, whereas seven patients showed stable disease at 4 weeks following 2 cycles of PRRT. Dosimetric analysis showed higher dose and retention time by IA approach. No significant peri-procedural or PRRT associated toxicity was seen. CONCLUSION: PRRT is a safe and effective therapeutic option for relapsed/refractory meningioma. The IA approach yields better dose delivery and should be routinely practised.

Malignant Minor Salivary gland neoplasms ofLarynx: Our Experience.

<br><b>Introduction:</b> Malignant minor salivary gland tumors are rare, accounting for fewer than 1% of all laryngeal cancers.</br> <br><b>Aim:</b> This study aims to share our experiences regarding clinical, radiological, pathological profiles and their management.</br> <br><b>Materials and methods:</b> The current study reviews 11 cases of malignant minor salivary gland tumors of the larynx treated surgically at our Institute between 2005 and 2019.</br> <br><b>Results:</b> The mean age of the patients was 54 years (range 38-75 years) with six females and five males in the series (1.2:1). Subglottis and trachea were the sites of origin in 54% of the cases, and hoarseness with dyspnea were the most common presenting symptoms. There were nine Adenoid cystic and two Mucoepidermoid carcinoma patients. Surgery was the primary mode of treatment.</br> <br><b>Conclusions:</b> Most of the larynx's malignant minor salivary gland tumors are submucosal in origin. The outcome and prognosis vary considerably based on the tumor's histology, grade, and stage.</br>.

Imaging-Based Patterns of Failure following Re-Irradiation for Recurrent/Progressive High-Grade Glioma.

BACKGROUND: Re-irradiation (ReRT) is an effective treatment modality in appropriately selected patients with recurrent/progressive high-grade glioma (HGG). The literature is limited regarding recurrence patterns following ReRT, which was investigated in the current study. METHODS: Patients with available radiation (RT) contours, dosimetry, and imaging-based evidence of recurrence were included in the retrospective study. All patients were treated with fractionated focal conformal RT. Recurrence was detected on imaging with magnetic resonance imaging (MRI) and/ or amino-acid positron emission tomography (PET), which was co-registered with the RT planning dataset. Failure patterns were classified as central, marginal, and distant if >80%, 20-80%, or <20% of the recurrence volumes were within 95% isodose lines, respectively. RESULTS: Thirty-seven patients were included in the current analysis. A total of 92% of patients had undergone surgery before ReRT, and 84% received chemotherapy. The median time to recurrence was 9 months. Central, marginal, and distant failures were seen in 27 (73%), 4 (11%), and 6 (16%) patients, respectively. None of the patient-, disease-, or treatment-related factors were significantly different across different recurrence patterns. CONCLUSION: Failures are seen predominantly within the high-dose region following ReRT in recurrent/ progressive HGG.

Machine-Learning-Based Radiomics for Classifying Glioma Grade from Magnetic Resonance Images of the Brain.

Grading of gliomas is a piece of critical information related to prognosis and survival. Classifying glioma grade by semantic radiological features is subjective, requires multiple MRI sequences, is quite complex and clinically demanding, and can very often result in erroneous radiological diagnosis. We used a radiomics approach with machine learning classifiers to determine the grade of gliomas. Eighty-three patients with histopathologically proven gliomas underwent MRI of the brain. Whenever available, immunohistochemistry was additionally used to augment the histopathological diagnosis. Segmentation was performed manually on the T2W MR sequence using the TexRad texture analysis softwareTM, Version 3.10. Forty-two radiomics features, which included first-order features and shape features, were derived and compared between high-grade and low-grade gliomas. Features were selected by recursive feature elimination using a random forest algorithm method. The classification performance of the models was measured using accuracy, precision, recall, f1 score, and area under the curve (AUC) of the receiver operating characteristic curve. A 10-fold cross-validation was adopted to separate the training and the test data. The selected features were used to build five classifier models: support vector machine, random forest, gradient boost, naive Bayes, and AdaBoost classifiers. The random forest model performed the best, achieving an AUC of 0.81, an accuracy of 0.83, f1 score of 0.88, a recall of 0.93, and a precision of 0.85 for the test cohort. The results suggest that machine-learning-based radiomics features extracted from multiparametric MRI images can provide a non-invasive method for predicting glioma grades preoperatively. In the present study, we extracted the radiomics features from a single cross-sectional image of the T2W MRI sequence and utilized these features to build a fairly robust model to classify low-grade gliomas from high-grade gliomas (grade 4 gliomas).

CT-Based Screening for Pulmonary Metastases in Head and Neck Squamous Cell Cancers: Diagnostic Accuracy and Cost Comparison with PET-CECT.

This study's objective was to compare detection rates of radiograph, computed tomography (CT), and positron emission tomography-contrast-enhanced computed tomography (PET-CECT) for pulmonary metastasis/synchronous primary lung tumors in head and neck squamous cell cancer (HNSCC) and its association with clinico-radio-pathological factors. Our retrospective study included 837 HNSCC patients from January 2012 to December 2017. Lung nodules were characterized on CT as benign, indeterminate, and metastatic. The true detection rate and statistical significance of associated risk factors were calculated. Risk factors for metastasis were determined using univariate and multivariate logistic regression models. Seventy-five (8.9%) patients had pulmonary metastasis and 3 (0.3%) had second lung primary. Detection rate of pulmonary metastasis by CT was higher (sensitivity-97.3%, specificity-97.2%) as compared to radiograph (sensitivity 49% and specificity 89%). Correlation was found between pulmonary and extra-pulmonary metastasis and N classification (P = 0.01, P = 0.02) and positive low jugular node (P = 0.001, P = 0.001). Using PET-CECT in place of CT costed an extra outlay of 7,033,805 INR (95,551.85 USD) while detecting distant metastasis in only 4 (0.47%) extra cases. Chest CT is a useful pulmonary metastases screening tool in advanced HNSCC patients with reasonable imaging cost as compared to PET-CT.

Anti-N-methyl-D-aspartate-receptor Encephalitis as a Harbinger of Pediatric HIV Infection.

Anti-N-methyl-D-aspartate-receptor (A-NMDAR) encephalitis is the most common type of autoimmune encephalitis in the pediatric age group. It is known to be triggered by viral infections such as herpes simplex infections. However, A-NMDAR encephalitis with HIV infection is a very rare event, with cases reported mostly in adults. The current report is of a previously healthy child who presented with recurrent vomiting, irritability, visual impairment, and new onset complex partial seizures and right somatosensory seizures with generalization occurring in clusters. Over a period of 3 weeks, he developed rapidly progressive bilateral painless visual loss, visual hallucinations, and behavioral changes. Brain magnetic resonance imaging (MRI) showed predominantly cortical symmetrical T2/FLAIR hyperintense signal change in parieto-occipito-temporal regions. The serum and cerebrospinal fluid were strongly positive for anti-NMDAR antibodies, and he also tested positive for HIV-1 antibodies acquired by vertical transmission. The patient and mother tested positive for HIV antibodies for the first time. Repeat MRI revealed gliosis in the parieto-occipito-temporal regions, and hippocampi showed volume loss and T2/FLAIR hyperintense signal change in the posterior thalami with patchy hyperintensities in the right putamen. The seizures subsided with immunomodulation along with anti-epileptic drugs, but he had residual cortical visual impairment on follow-up. This is the first report of A-NMDAR encephalitis presenting as a harbinger of HIV infection in a child. This calls for testing for A-NMDAR antibodies in children with HIV infection presenting with neurological or neuropsychiatric manifestations.

Fibromatoses of Head and Neck: Case Series and Literature Review.

OBJECTIVE: The objective of this study was to retrospectively review clinical data, management protocols, and clinical outcomes of patients with fibromatoses of head and neck region treated at our tertiary care center. METHODS: We retrospectively reviewed the medical records of 11 patients with confirmed histopathological diagnosis of fibromatosis registered in the Department of Head and Neck Surgery at Tata Memorial Centre, India, between 2009 and 2019. Various clinical and pathological features and treatment modalities were evaluated. RESULTS: Age at diagnosis ranged between 18 and 74 years, with a median age of 36 years. The female-to-male ratio was 5:6. Supraclavicular fossa (n=4) was the most common subsite of origin in the neck (n=8). The lateral (n=2) and posterior cervical regions (n=2) were other common neck subsites. Less commonly involved sites were the mandible (n=1), maxilla (n=1), and thyroid (n=1). A total of eight patients underwent surgery at other centers before being referred to us for further management. Out of a total 11 patients, nine patients had unresectable disease at presentation. Six of the patients with unresectable disease received a combination of weekly doses of vinblastine 6 mg/m2 and methotrexate 30 mg/m2 for a median duration of 6 months (range 6-18 months) followed by hormonal therapy with tamoxifen. Three patients received metronomic chemotherapy followed by hormonal therapy. One treatment-naive patient with fibromatosis of posterior cervical (suboccipital) region underwent R2 resection (excision of bulk of the tumor with preservation of critical structures) at our center along with adjuvant radiotherapy. One pregnant patient reported to us after undergoing surgery outside and defaulting radiotherapy. During median follow-up of 29 months (range 1-77 months), six patients had stable disease, and four patients had disease reduction. Disease progression was seen in one patient. The two-year progression-free survival (PFS) was 90% (95% CI 70%-100%). CONCLUSION: Gross residual resection (R2) was the mainstay of surgical treatment in our series, as obtaining clear surgical margins is seldom possible in these locally aggressive tumors. Radiotherapy, chemotherapy, and hormonal therapy are the other preferred and more conservative treatment modalities. The goal of surgery should be preserving function with minimal or no morbidity. As fibromatoses in the head and neck region are extremely rare, their treatment awaits the development of standard treatment protocols.

Nightmares with a starry sky - Treating neurocysticercal encephalitis, how far to go.

Cysticercosis, an infection caused by the larval stage of tapeworm Taenia solium, is the most common parasitic disease of the human nervous system and the single most common cause of acquired epileptic seizures in the developing world. Here, we describe the stormy course of a 67-year-old female with neurocysticercosis (NCC) having a recurrent encephalitic presentation. She went through the most severe spectrum of this disease, namely NCC encephalitis and disseminated cysticercosis and had a classical starry sky brain in neuroimaging. In contrary to the popular practice of avoiding antihelminthic drugs in such extreme presentation, as a desperate measure, we had to use albendazole in this case, which showed clinical and radiological improvement.

Dome-Shaped Pituitary Enlargement in Primary Hypothyroidism: Avoiding Neurosurgical Interventions.

We describe three cases of primary hypothyroidism which presented initially to neurosurgery department with pituitary hyperplasia. We have found a novel pattern of 'dome-shaped' enlargement of pituitary in MRI of these patients. Out of these 3 patients, in two of them, the planned surgery was deferred when endocrinologists were consulted and the pituitary hyperplasia completely resolved with levothyroxine treatment. In the third case, pituitary surgery was already performed before endocrinology consultation and histopathology revealed thyrotroph hyperplasia. The hyperplastic lesions described typically have a homogenous symmetrical 'dome' shaped architecture unlike the non-functioning pituitary adenoma (NFPA), which usually might often be of varying shapes and homogeneity. Analysis of pituitary images from similar case reports published in literature, also showed this typical 'dome' shaped pituitary enlargement. This imaging characteristic can be a clue to look for underlying hormone deficiency, especially in primary hypothyroidism. Therefore, a thorough endocrine evaluation especially looking for primary hypothyroidism in such dome-shaped pituitary lesions are mandatory to prevent unwarranted neuro-surgical intervention as treatment of primary hypothyroidism may result in resolution of the abnormal enlargement.

Bruns Syndrome - An Unusual Presentation.

Bruns syndrome is characterized by attacks of sudden severe headache, vomiting, and vertigo precipitated due to abrupt movements of the head due to presence of mobile deformable intraventricular lesion causing episodic obstructive hydrocephalus. Proposed underlying mechanism is intermittent or positional CSF obstruction resulting from ball-valve mechanism. Most common etiologies are NCC and intraventricular tumors. Here we present an unusual case of Bruns syndrome that was initially MRI negative.

The SRG rat, a Sprague-Dawley Rag2/Il2rg double-knockout validated for human tumor oncology studies.

We have created the immunodeficient SRG rat, a Sprague-Dawley Rag2/Il2rg double knockout that lacks mature B cells, T cells, and circulating NK cells. This model has been tested and validated for use in oncology (SRG OncoRat®). The SRG rat demonstrates efficient tumor take rates and growth kinetics with different human cancer cell lines and PDXs. Although multiple immunodeficient rodent strains are available, some important human cancer cell lines exhibit poor tumor growth and high variability in those models. The VCaP prostate cancer model is one such cell line that engrafts unreliably and grows irregularly in existing models but displays over 90% engraftment rate in the SRG rat with uniform growth kinetics. Since rats can support much larger tumors than mice, the SRG rat is an attractive host for PDX establishment. Surgically resected NSCLC tissue from nine patients were implanted in SRG rats, seven of which engrafted and grew for an overall success rate of 78%. These developed into a large tumor volume, over 20,000 mm3 in the first passage, which would provide an ample source of tissue for characterization and/or subsequent passage into NSG mice for drug efficacy studies. Molecular characterization and histological analyses were performed for three PDX lines and showed high concordance between passages 1, 2 and 3 (P1, P2, P3), and the original patient sample. Our data suggest the SRG OncoRat is a valuable tool for establishing PDX banks and thus serves as an alternative to current PDX mouse models hindered by low engraftment rates, slow tumor growth kinetics, and multiple passages to develop adequate tissue banks.

Brain and Spinal Cord Lesions in Leprosy: A Magnetic Resonance Imaging-Based Study.

Neurotropism and infiltration by Mycobacterium leprae of peripheral nerves causing neuropathy are well established, but reports of central nervous system (CNS) damage are exceptional. We report CNS magnetic resonance imaging (MRI) abnormalities of the brain and spinal cord as well as lesions in nerve roots and plexus in leprosy patients. Eight patients aged between 17 and 41 years underwent detailed clinical, histopathological, and MRI evaluation. All had prominent sensory-motor deficits with hypopigmented and hypo/anesthetic skin patches and thickened peripheral nerves. All demonstrated M. Leprae DNA in affected peripheral nerve tissue. All received multidrug therapy (MDT). Two patients had brainstem lesions with enhancing facial nuclei and nerves, and one patient had a lesion in the nucleus ambiguus. Two patients had enhancing spinal cord lesions. Follow-up MRI performed in four cases showed resolution of brainstem and cord lesions after starting on MDT. Thickened brachial and lumbosacral plexus nerves were observed in six and two patients, respectively, which partially resolved on follow-up MRI in the two cases who had reimaging. The site and side of the MRI lesions corresponded with the location and side of neurological deficits. This precise clinico-radiological correlation of proximal lesions could be explained by an immune reaction in the gray matter corresponding to the involved peripheral nerves, retrograde axonal and gray matter changes, or infection of the CNS and plexus by lepra bacilli. Further study of the CNS in patients with leprous neuropathy is needed to establish the exact nature of these CNS MRI findings.

Imaging of dentate nucleus pathologies; a pictorial essay.

Dentate nucleus is affected in a wide variety of conditions. Magnetic resonance imaging of the brain is the diagnostic modality of choice for delineating the signal characteristics, which helps in narrowing down a vast list of differentials for conditions affecting the dentate. Computed tomography plays an important role, especially for pathologies associated with calcification of dentate nucleus.