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Case Presentation A 3-year-old female with insignificant past medical history presented with 6 weeks of headaches, emesis, and lethargy. MR imaging identified a heterogeneously enhancing right cerebellar hemispheric mass and obstructive hydrocephalus. Gross total resection was performed without complications; pathology revealed classical WHO grade 4 medulloblastoma (MB). MR imaging of the spine and cerebrospinal fluid testing were negative for disseminated disease. Treatment for standard risk medulloblastoma was initiated, comprising proton craniospinal irradiation with posterior fossa boost and concurrent vincristine, followed by adjuvant chemotherapy with vincristine, lomustine, cisplatin, and cyclophosphamide as standard of care. Next generation sequencing of the tumor tissue performed using a high-multiplex PCR-based NGS panel was negative for alteration of the SMO, PTCH1 and CTBNN1 genes. Further molecular characterization via methylation profiling demonstrated the sonic hedgehog (SHH) molecular subtype. Prior to initiation of chemotherapy, renal ultrasound was performed and identified congenitally absent right kidney; audiology evaluation was unremarkable. Discussion In patients with Gorlin syndrome, cases of unilateral renal agenesis in association with germline SHH-pathway mutations have been reported [1]. SHH signaling is implicated in multiple steps in the development of the urinary system [2]. Outside Gorlin syndrome, however, to the best of our knowledge unilateral renal agenesis coinciding with SHH-driven MB has not been reported. Our patient notably lacks any clinical stigmata of Gorlin syndrome (skeletal abnormalities, skin pits, macrocephaly) and does not exhibit the characteristic germline genetic abnormalities that define GS (PTCH1 mutation or 9q22.3 microdeletion). There are important treatment implications for patients with the constellation of abnormalities we describe here, particularly regarding the requisite frequent monitoring of renal function during multi-agent chemotherapy courses. Our patient tolerated chemoradiation well, and is currently on maintenance chemotherapy with favorable course to date.

Purpose of Review Chemotherapy-induced nausea and vomiting (CINV) is a common cause of acute morbidity that impacts quality of life in children receiving cancer treatment. Here, we review the evolution of CINV prophylaxis guidelines in children, with an emphasis on the literature published in the last 5 years, to bring the reader up to date. Recent Findings Recent studies have led to the adoption of the “triple therapy” regimen of antiemetic prophylaxis (a 5-HT3 antagonist, dexamethasone, and a neurokinin-1 antagonist) as the backbone of recommendations for the prevention of CINV in children. Areas of new data include the addition of aprepitant and inclusion of palonosetron as a non-inferior 5-HT3 antagonist. In addition, there are emerging pediatric data informing patient-derived risk factors associated with CINV risk and classification of antineoplastic drugs based on emetogenicity. Summary Several recent pediatric studies have shaped published guidelines for CINV prophylaxis in children.

Tumors escape immune surveillance by activating the inhibitory checkpoint programmed death 1 (PD-1)/programmed death ligand 1 (PDL-1) pathway to attenuate T cell responses and render them functionally exhausted. Antibodies targeting the PD-1/PDL-1 immune checkpoint pathway rescue anti-tumor function and have shown remarkable success in treating several adult cancers, with PDL-1 positive tumors demonstrating the most objective responses. There are limited data on PDL-1 expression in pediatric central nervous system (CNS) tumors. We evaluated PDL-1 expression in formalin-fixed, paraffin-embedded tumor specimens from 37 pediatric patients via immunohistochemistry. We used a rabbit anti-human monoclonal anti PDL-1 antibody by Spring BioSciences (M4424). PDL-1+ positivity was quantified as either 50% membrane staining. Tumors with >5% membrane staining were scored as positive. The proportion of PDL-1+ tumors was 100% for anaplastic pleomorphic xanthoastrocytoma (4/4), 80% for pilocytic astrocytoma (4/5), 67% for glioblastoma (4/6), 67% for ependymoma (2/3), 50% for anaplastic astrocytoma (1/2), 50% for primitive neuroectodermal tumor (1/2), 25% for medulloblastoma (1/4), and 0% for pineoblastoma (0/6). Of the remaining 5 tumors tested, 2 were PDL-1+ (anaplastic ganglioglioma, anaplastic oligodendroglioma), and 3 were negative for PDL-1 expression (recurrent astrocytoma, atypical choroid plexus papilloma, choroid plexus carcinoma). Interestingly, all glioblastoma tumors (4/4) had >50% PDL-1 expression, whereas all pineoblastoma (6/6) tumors had