Algorithmic approach utilizing histology and immunohistochemistry for the current classification of diffuse glioma.

INTRODUCTION: Diffuse glioma constitutes 28% of primary brain tumors. Until recently morphologic appearance was the only criterion for classifying these tumors. However, WHO 2016 incorporates molecular information in the primary diagnosis of gliomas such as Isocitrate dehydrogenase 1 (IDH1), Alpha thalassemia/mental retardation syndrome X inked (ATRX) as well as 1p/19q codeletion on FISH. In a resource-limited setup where FISH is not available, Alpha internexin (INA) has been suggested as a surrogate IHC marker. MATERIAL AND METHODS: Cross-sectional study conducted in the Department of Pathology for two years. Tissue blocks and clinical as well as radiological details were obtained from departmental archives. After assessing the morphologic details, routine IHC markers such as GFAP, Ki67 and P53 along with molecular markers like IDH-1, ATRX, and lNA were applied. RESULTS: Out of 55 cases of diffuse glioma, 23 cases of astrocytoma and 32 cases of oligodendroglioma with an overall mean age of presentation of 41.49 ± 12.47 years. IDH-1 expression among diffuse glioma was 89.1% in our study. Alteration in the ATRX gene expression was observed in 95.7% of astrocytomas. 75% of oligodendrogliomas expressed INA with no significant difference in expression between the two grades. Based on the algorithmic approach using molecular surrogate markers, diffuse gliomas were categorized into six distinct groups. IDH-mutant, ATRX loss of expression astrocytoma and IDH-mutant, INA positive oligodendroglioma are two categories that do not require further molecular testing. This comprises 72.7% of the cases and these do not warrant further workup. CONCLUSION: Implementation of combined phenotypic-genotypic diagnosis with the use of histomorphology and immunohistochemical surrogates for molecular genetic alterations will yield more homogeneous and narrowly defined diagnostic entities which will provide better prognostication and definitive treatment. It also is cost-effective in a resource-limited setup.

Intracranial abscess due to Prevotella bivia: First case report from India.

The association of Prevotella bivia (P. bivia), a Gram negative obligate anaerobic bacillus with brain abscess has been rarely reported. We hereby, report a case of brain abscess in a 50-year-old man, who suffered a head trauma followed by decompression surgery 10 months ago. Aspirated pus sample grew Methicillin resistant Staphylococcus aureus (MRSA) and P. bivia sensitive to metronidazole. The patient recovered well after a brain abscess evacuation surgery and post-operative metronidazole therapy, confirming the pathogenic role of P. bivia in this case.

Uncommon isolation of Desulfovibrio vulgaris from a depressed fracture wound on the forehead.

Desulfovibrio spp. are gram negative, obligate anaerobes capable of reducing sulfate. They have caused infections in humans, but very rarely. They are slow growers and difficult to identify. Hence, they are often overlooked and their actual presence goes unnoticed. Here, we describe a case of a 15- year old boy who was involved in a road traffic accident and he presented with seropurulent discharge from a depressed fracture wound on the forehead. Desulfovibrio vulgaris (D.vulgaris), was isolated from the pus discharge, the first to be reported. The characteristic desulfoviridin pigment production in the organism aided in the identification. The infection was successfully managed with pain reliever and course of amoxicillin - clavulanic acid and linezolid.

Trigeminal schwannoma of the sphenoid sinus--report of a rare entity.

Schwannomas are common slow growing benign tumors. About 25-45% of all schwannomas arise in the head and neck region. Less than 4% of these tumors are found in sinonasal regions and usually affect nasal ethmoid. There are very few case reports of a schwannoma arising from the sphenoid sinus. We report a case of sphenoid sinus schwannoma treated by microscopic decompression and review the relevant literature.

Acute pyogenic necrotizing encephalomyelitis: a fulminant and fatal infection.

In this report the authors describe a rare case of a fulminant, pyogenic, necrotizing infection of the spinal cord and brain. Necrotizing lesions of the brain and spinal cord are usually infectious in origin and are associated with high rates of morbidity and death. Although the pathogens responsible have been identified in a few instances, the causal factors remain unknown in many cases. An 11-year-old girl developed acute, rapidly progressive paraplegia with bladder involvement and sensory loss below T-10. She had been treated recently for a Staphylococcus aureus infection of the knee joint precipitated by a penetrating injury with organic matter in the aftermath of a cyclone. Although appropriate antibiotic therapy was instituted, the spinal cord infection progressed to involve the entire spinal cord, brainstem, and brain. This fulminant course was marked by a rapid deterioration in the patient's clinical condition, ultimately leading to her death. Magnetic resonance imaging demonstrated a previously undescribed pattern of longitudinal enhancement along the spinal cord, as well as the white matter tracts in the brainstem and brain. The possible route of spread of infection along the neuraxis is postulated to be the potential space along the white matter tracts. Treatment is not standardized due to the rarity of the condition.