Molecular Characterization of IDH Wild-type Diffuse Astrocytomas: The Potential of cIMPACT-NOW Guidelines.

IDH wild-type (wt) grade 2/3 astrocytomas are a heterogenous group of tumors with disparate clinical and molecular profiles. cIMPACT-NOW recommendations incorporated in the new 2021 World Health Organization (WHO) Classification of Central Nervous System (CNS) Tumors urge minimal molecular criteria to identify a subset that has an aggressive clinical course similar to IDH -wt glioblastomas (GBMs). This paper describes the use of a panel of molecular markers to reclassify IDH -wt grade 2/3 diffuse astrocytic gliomas (DAGs) and study median overall survival concerning for to IDH -wt GBMs in the Indian cohort. IDH -wt astrocytic gliomas (grades 2, 3, and 4) confirmed by IDHR132H immunohistochemistry and IDH1/2 gene sequencing, 1p/19q non-codeleted with no H3F3A mutations were included. TERT promoter mutation by Sanger sequencing, epidermal growth factor receptor amplification, and whole chromosome 7 gain and chromosome 10 loss by fluorescence in situ hybridization was assessed and findings correlated with clinical and demographic profiles. The molecular profile of 53 IDH -wt DAGs (grade 2: 31, grade 3: 22) was analyzed. Eleven cases (grade 2: 8, grade 3: 3) (20.75%) were reclassified as IDH -wt GBMs, WHO grade 4 ( TERT promoter mutation in 17%, epidermal growth factor receptor amplification in 5.5%, and whole chromosome 7 gain and chromosome 10 loss in 2%). Molecular GBMs were predominantly frontal (54.5%) with a mean age of 36 years and median overall survival equivalent to IDH -wt GBMs (18 vs. 19 mo; P =0.235). Among grade 2/3 DAGs not harboring these alterations, significantly better survival was observed for grade 2 versus grade 3 DAGs (25 vs. 16 mo; P =0.002). Through the incorporation of a panel of molecular markers, a subset of IDH -wt grade 2 DAGs can be stratified into molecular grade 4 tumors with prognostic and therapeutic implications. However, IDH -wt grade 3 DAGs behave like GBMs irrespective of molecular profile.

Surgical Track and Scalp Implantation Following Intraventricular Meningiomas Excision: A Report with Review of Literature.

Meningiomas are benign intracranial neoplasms arising from arachnoid cap cells. High grade meningiomas are uncommon and metastasis from these is an extremely rare event. Commonest sites of metastasis from high grade meningiomas include lung, liver, lymph nodes and bone. It is unusual for meningiomas to recur in the surgical track following excision. More so, it is even the rarest phenomenon for a meningioma to implant in subgaleal location. Various mechanisms have been proposed for the scalp implantation vis-à-vis CSF dissemination, direct surgical implantation etc., It may apply to all histological grades of meningiomas. Even the benign tumors have been shown to seed at postoperative scar. This seems to have provoked our interest to review the literature regarding this scalp implantation. We have reviewed all the cases where surgical excision of intracranial meningiomas has led to seeding of surgical track as well as scalp. We have discussed the various genetic aberrations that can guide us regarding the progression of the tumor and prognosis. We also report a case of surgical track and scalp implantation of an atypical intraventricular meningioma following excision.