Meningiomas are the most common type of intracranial brain tumors in adults. The majority of meningiomas are benign with a low risk of recurrence after resection. However, meningiomas defined as grades II or III, according to the 2016 World Health Organization (WHO) classification, termed high-grade meningiomas, frequently recur, even after gross total resection with or without adjuvant radiotherapy. Boron neutron capture therapy (BNCT) and photodynamic therapy (PDT) are novel treatment modalities for malignant brain tumors, represented by glioblastomas. Although BNCT is based on a nuclear reaction and PDT uses a photochemical reaction, both of these therapies result in cellular damage to only the tumor cells. The aim of this literature review is to investigate the possibility and efficacy of BNCT and PDT as novel treatment modalities for high-grade meningiomas. The present review was conducted by searching PubMed and Scopus databases. The search was conducted in December 2019. Early clinical studies of BNCT have demonstrated activity for high-grade meningiomas, and a phase II clinical trial is in progress in Japan. As for PDT, studies have investigated the effect of PDT in malignant meningioma cell lines to establish PDT as a treatment for malignant meningiomas. Further laboratory research combined with proper controlled trials investigating the effects of these therapies is warranted.

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Although the rhomboid lip is a well-known structure constructing the foramen of Luschka, less attention has been directed to the structure for posterior fossa microsurgeries. The authors report two cases of the hemifacial spasm (HFS) with a large rhomboid lip, focusing on the importance of the structure during microvascular decompression. A 59-year-old female presenting with left HFS was admitted to our hospital. A preoperative magnetic resonance image demonstrated an offending artery at the root exit zone of the VII nerve. The patient underwent microvascular decompression through the lateral suboccipital approach. The intraoperative findings showed that a large rhomboid lip adhered to the IX and X cranial nerves and prevented the exposure of the root exit zone of the VII cranial nerve. The rhomboid lip was meticulously separated from the cranial nerves so that the choroid plexus of the foramen of Luschka and the rhomboid lip could be safely lifted with a spatula, and the offending artery was successfully detached from the root exit zone. In another case of a 60-year-old male, the rhomboid lip was so large that it needed to be incised before separating it from the lower cranial nerves. In each case, the HFS was resolved following surgery without any new deficits. The large rhomboid lip adhering to the cranial nerves should be given more attention in the posterior fossa surgeries and should be managed based on the microsurgical anatomy for preventing unexpected lower cranial nerve deficit.

The development of potent and selective therapeutic approaches to glioblastoma (GBM) requires the identification of molecular pathways that critically regulate the survival and proliferation of GBM. Glioblastoma stem-like cells (GSCs) possess stem-cell-like properties, self-renewal, and differentiation into multiple neural cell lineages. From a clinical point of view, GSCs have been reported to resist radiation and chemotherapy. GSCs are influenced by the microenvironment, especially the hypoxic condition. N-myc downstream-regulated gene 1 (NDRG1) is a tumor suppressor with the potential to suppress the proliferation, invasion, and migration of cancer cells. Previous studies have reported that deregulated expression of NDRG1 affects tumor growth and clinical outcomes of patients with GBM. This literature review aimed to clarify the critical role of NDRG1 in tumorigenesis and acquirement of resistance for anti-GBM therapies, further to discussing the possibility and efficacy of NDRG1 as a novel target of treatment for GBM. The present review was conducted by searching the PubMed and Scopus databases. The search was conducted in February 2022. We review current knowledge on the regulation and signaling of NDRG1 in neuro-oncology. Finally, the role of NDRG1 in GBM and potential clinical applications are discussed.