Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery. Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery. Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs.

Background: The most common glial tumor is the glioblastoma, and the prognosis remains dismal despite a multimodal therapeutic approach. The role of radiosurgery for the treatment of glioblastomas has been evaluated in several studies with some benefit at the recurrent stage. We evaluate the results of the protocol administered at the Gamma Knife unit administering radiosurgery as a boost to metabolic active parts of the tumor after the patient had completed traditional external beam radiotherapy (XBRT) as part of the Stupp protocol for high-grade gliomas. Methods: This is a retrospective analysis of seven patients with newly diagnosed glioblastomas who were treated with Gamma Knife radiosurgery as a boost after receiving XBRT as part of the Stupp protocol. The target of radiation was determined according to the findings of the C-methionine PET scan in relation to magnetic resonance images. The primary end point of this study was to determine the progression-free survival (PFS) from the time of diagnosis. Results: The median age of patients was 48.8 years and the mean Karnofsky performance score was 92.8%. The median PFS was 12.4 months. No radiation adverse effects were documented. Conclusion: Stereotactic radiosurgery is safe to use in the upfront treatment for these patients and appears to have a beneficial role in improving the PFS. This beneficial role seems to be conditioned not only by the time the treatment is administered but also where the radiation dose is targeted to.

The 2021 World Health Organization classification for brain tumors introduced several new entities and categories. Tumors of uncertain differentiation are a new subcategory that includes the intracranial mesenchymal tumor, FET-CREB fusion-positive; the CIC-rearranged sarcoma; and the Primary intracranial sarcoma, DICER1-mutant. A search was made in Pubmed and Google Scholar to include all articles with the term “uncertain differentiation”, “Mesenchymal, non-meningothelial”, “FET-CREB fusion positive”, “DICER1-mutant sarcoma” and “CIC-Rearranged sarcoma” in their title. These articles were reviewed to draft a concise review on this subject. This review on CNS non-meningothelial mesenchymal tumors is meant to provide an update with diagnostic, prognostic, and therapeutic implications. Tumors of uncertain differentiation include a variety of mesenchymal, non-meningothelial tumors that have distinct molecular characteristics and consequently behave in a very particular matter. Given that these tumors have been described only recently, there is still an important lack of information regarding the most appropriate treatment and prognosis.

Background: Extent of resection (EOR) plays a major role in the prognosis on patients with gliomas, although the postoperative functionality of the patient is of great importance as well. It is why many surgeons advocate to not operate extensively on tumors that involve eloquent regions such as the central lobe. Recent series have demonstrated that it is possible to achieve extensive resections in this area without significantly affecting the functional outcome for these patients. We illustrate this issue with the experience obtained at the National Institute of Neurology and Neurosurgery in Mexico City. Methods: This is an observational and retrospective study that included patients that received surgical resection for intracranial gliomas that involved the central lobe at the National Institute of Neurology and Neurosurgery of Mexico, between January 2017 and May 2020. Demographic and clinical variables of the patients at the time of diagnosis were collected as well as tumor morphological variables, surgical adjuncts, and clinical outcomes. Statistical analysis was performed with SPSS software. Results: A total of 28 patients were included in the study with 43% of patients having a motor deficit before surgery. The average EOR was 88.6%. Patients presented with worsening of their motor status in the immediate postoperative period in 21% of the cases, although most of the patients recovered within the 1^st month of follow-up. After analyzing all variables, not having a presurgical motor deficit was a statistically significant risk factor for developing a new motor deficit in the immediate postoperative period (P: 0.02). Conclusion: A resective surgery for gliomas near or within the central lobe can be performed safely and a satisfactory motor outcome for patients can be achieved without sacrificing the EOR. An intact presurgical motor status is a risk factor for developing a new deficit after surgery.