Skull base surgeries developed in 1980s and 1990s with departments of otorhinolaryngology and plastic surgery. Otorhinolaryngologists and plastic surgeons taught us a lot such as skull base anatomy, skull base and facial osteotomy, techniques of skull base reconstruction, and principle of en bloc resection for malignant tumors. In 2000s, skull base surgeries evolved with extended endonasal endoscopic surgeries. Skull base surgeries in future must be sweet for the patients: safe without complications, precise for lesions, and less invasive. Moreover, skull base surgeries need to treat more patients with excellent long-term outcome.

Various kind of paraventricular tumors, such as germinoma, are sensitive to chemoradiotherapy. However, they usually develop hydrocephalus and are hard to resect. Therefore, neuroendoscopic tumor biopsy and endoscopic third ventriculostomy are usually performed. Paraventricular tumors include glioma, malignant lymphoma, and pineal tumor among others. We used different approaches and therapeutic management depending on the type of tumor. For glioma, particularly malignant glioma, preoperative angiography should be performed to assess tumor vascularity. At the time of endoscopic operation, an electrohemostasis instrument should be prepared, and the operation should be performed by two experts because of the difficulty of the procedure. As glioma often develops under the ventricular wall, the ependymal layer is first removed using forceps. Subsequently, on-site biopsy is performed deeply until some bleeding is detected. For malignant lymphoma, this tumor is often prominent in the intraventricular wall in which bleeding control is relatively easy and the pathology is always homogeneous. Therefore, biopsy and pathological diagnosis are readily achieved. As treatment of malignant lymphoma with steroids often vanish in tissue sample, steroids should not be used preoperatively. For pineal tumor, achieving intraoperative hemostasis is rarely difficult; however, care should be taken so that dissemination of tumor cells from the heterogeneous tissue is prevented. Therefore, sufficient irrigation after biopsy should be performed.

Radiomics is a rapidly emerging brain tumor image analyzing technique. Key features that outstands in radiomics is its ability to quantitatively analyze qualitative images with special care taken for texture features of the image. This method allows cross-patient analysis taking advantage of image registration and high performance computational power. In this review article, the author attempted to clarify the most basic aspects of radiomics in brain tumor image analysis.

Pilocytic astrocytoma is a benign World Health Organization grade 1 tumor and usually occurs in young patients. This tumor can occur in adults, yet relatively few arise in those who are older than 50 years. The tumor histology is characterized by a biphasic pattern with compacted bipolar cells associated with Rosenthal fibers and loose-textured multipolar cells associated with microcysts and eosinophilic granular bodies/hyaline droplets. Tumor-growth is always slow, and occasionally regressive changes are observed mainly for tumors in children and associated with neurofibromatosis type 1.

We previously reported a unique case of pilocytic astrocytoma diagnosed for 64-year-old woman. This case was noteworthy in two points: the patient was an elderly adult without clear comorbidity; the patient’s tumor spontaneously regressed in short term before surgery. Here we report the follow-up clinical course.

She was uneventfully followed up without additional therapy after complete lesionectomy, but the tumor recurred at the 45-month after surgery. While the histological pattern of recurred tumor imitated that of diffuse astrocytoma, the immunohistochemical profiles did not changed from the first presentation.

Several reports provided the information about non-indolent clinical courses of adult-onset pilocytic astrocytoma. We should be cautious about this entity and the subtyping of IDH wild type tumor group to which pilocytic astrocytoma belongs.