Clinical profile, treatment, histopathological, immunohistochemical, and molecular analyses of pilocytic astrocytoma- an eight year study from a tertiary health care centre in North East India

Purpose: Pilocytic astrocytoma (PA) is a central nervous system (CNS) World Health Organization (WHO) grade 1 glial tumor that is highly prevalent in children and young adults. The main aim of the study was to assess the frequency, clinicopathological features and treatment of PAs along with their immunohistochemical and molecular analyses. Methods: : Approximately, 144 glial tumors were diagnosed in patients from 3 to 75 yrs of age from January 2015 to March 2022. The tumors were classified according to 2021 CNS WHO classification. Nine pediatric PA patients were identified and their clinical data analyzed. Immunohistochemistry (IHC), fluorescence in-situ hybridization (FISH) and molecular analysis using the real time polymerase chain reaction (RT-PCR) were performed for the PAs. Standard deviations were calculated using the Microsoft excel for statistical validations. Results: : The mean age of the glioma patients was 41.7 yrs ± 18.2 with a male/female ratio of 1.3:1. The most common form of glial tumor was found to be astrocytoma CNS WHO grade 2 (31.9 %). Other frequently occurring tumors were astrocytoma CNS WHO grade 3 (29.2 %), astrocytoma CNS WHO grade 4 (13.9 %), diffuse astrocytoma CNS WHO grade 2 (7.4 %), PA CNS WHO grade 1 (6.9 %), and oligodendroglioma CNS WHO grade 3 (4.2 %). The pediatric PA cohort had a mean age of 9.2 yrs ± 4.9 with a male/female ratio of 2:1. Glial fibrillary acidic protein (GFAP) positive immunostaining and retention of transcriptional regulator ATRX expression was seen in all the tested PAs. None of the PAs showed isocitrate dehydrogenase (IDH1), MIB1, and tumor protein p53 expression. The KIAA1459-BRAF fusion was detected in four PAs. Surgical intervention with total or radical tumor excision was performed for the PA patients. Most PA patients exhibited improved condition post-surgery. Conclusion: With the advent of healthcare and newer diagnostic facilities there is increased incidence of glial tumors in developing countries. Combination of histological, immunohistochemical, and molecular analysis is very important for the diagnosis, accurate treatment, and prognosis of PA patients.