Pediatric brain tumors are the leading cause of cancer-related death in children. Diagnosis cur-rently relies on surgical biopsy to obtain tumor tissue for histological analysis. There is a great need for less invasive approaches to molecularly profile tumors and monitor therapeutic response. Liquid biopsy analysis of circulating tumor biomarkers in biofluids like cerebrospinal fluid (CSF) and blood offers a promising minimally invasive strategy. This review discusses recent advances in developing liquid biopsy assays using next-generation sequencing, digital PCR, and emerging techniques to detect circulating tumor DNA (ctDNA), cells (CTCs), and exosomes in pediatric brain tumors. The ability to use these circulating biomarkers for non-invasive diagnosis, thera-peutic targeting, tracking response to therapy, and understanding resistance mechanisms is ex-amined. Technical and clinical validation challenges to translate liquid biopsies into routine clin-ical practice are also discussed.

Chronic rhinosinusitis (CRS) can have a significant impact on quality of life. With persistent symptoms and the failure of initial medical treatments, surgical management is indicated. Despite the excellent results of endoscopic sinus surgery for persistent CRS, it is quite a challenging procedure for frontal sinusitis given the complex anatomy and location of the frontal sinus. Frontal sinus cells significantly contribute to the complexity of the frontal sinus, and numerous studies have sought to establish their association with sinusitis. This review offers a comprehensive understanding of the frontal sinus cells, their different classifications, their prevalence among different populations, and their relationship to sinusitis. After an extensive review of the current literature, the International Frontal Sinus Anatomy Classification (IFAC) is the most recent classification method and a preferred practical preoperative assessment tool. Although the Agger Nasi Cell is the most prevalent cell among all reported populations, ethnic variations are still influencing the other cells' distribution. Studies are inconsistent in reporting a relationship between frontal sinus cells and sinusitis, and that is mainly because of the difference in the classification method used. More research using a standardized classification method is needed to understand the association between frontal sinus cells and sinusitis.