Although meningioma is the most frequently diagnosed intracranial tumor and accounts for approximately one-third of cases of all tumors of the central nervous system, knowledge concerning the natural course of meningioma remains scarce. Surgery is usually considered to be essential for symptomatic types of meningiomas. However, for asymptomatic types of meningiomas, the use of surgical treatment is controversial. Certain factors such as patient age, ADL, tumor size, and tumor location can be used to determine whether surgery is needed. At Kumamoto University, we analyzed approximately 600 cases of asymptomatic meningioma and found that 37% of the patients with meningioma did not experience any symptoms or adverse events when they were followed for more than 5 years. In addition, only 16% of the patients with asymptomatic meningiomas developed symptoms during the follow-up period. We should understand that there are many patients with asymptomatic meningioma who do not necessarily need surgery. Furthermore, for some patients with asymptomatic meningioma, observation and follow-up by magnetic resonance imaging or computed tomography may be the best strategy for treatment.

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  Treating petrous apex and petroclival meningiomas requires advanced surgical technique and extensive experience. In particular, in cases with strong adhesions to surrounding structures, the conflict between “functional preservation” and “resection rate” becomes a problem. However, because meningiomas in these areas are also pathologically benign, the ideal treatment is to perform maximum resection without any complications, suppress the recurrence rate, and maintain the patient's quality of life (QOL) over a long period of time. Not only improvements in surgical techniques, but also the overall ability to judge specific aspects of treatment, including follow-up, multi-staged surgeries, and radiation therapy, and a well-balanced treatment approach are demanded. In addition, the latest advancements in diagnostic imaging techniques have been remarkable, and not only the spatial relationships with surrounding structures, the degree of adhesion, the tumor blood flow and the stiffness, but also the growth and recurrence rates of the tumor itself are becoming increasingly predictable.

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  The first-line of treatment for acromegaly is surgery. Therefore improving of surgical intervention is very important for the treatment outcome of acromegaly. However, it is difficult to treat growth hormone (GH) producing pituitary adenomas with cavernous invasion by surgery alone ; additional medical treatment is needed for the complementary treatment of these cases. Additionally, transsphenoidal surgery is a basic method for treating acromegaly. Endoscopic surgery has also been widely used, either as pure endoscopic surgery or microscopic surgery-assisted endoscopy. The overall surgical outcome success rate for acromegaly is 70%, and further medical treatment is prescribed for patients with incomplete surgical outcomes. Somatostatin analogs (octreotide and lanreotide) are the first-line medications for acromegaly, and the normalization rate of insulin-like growth factor-I (IGF-I) is about 50-70%. Dopamine agonist or GH receptor antagonist are also used for treating acromegaly. Although economically more viable than somatostatin analogs and GH receptor antagonists, oral dopamine agonists have a lower efficacy. GH receptor antagonist has a high efficacy ; however, it has many side effects. Stereotactic irradiation is also a useful treatment choice for acromegaly. The normalization rate of IGF-I after stereotactic irradiation is about 60-70%, although it requires several years for proper normalization. The surgical and medical therapy options for acromegaly are the focused of this review.

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  Skull base and paracervical chordomas are rare tumors originating from ectopic remnants of the embryonal notochord at the spheno-occipital synchondrosis. Although the first choice of treatment is surgical resection, complete resection is difficult due to the tumors' close proximity to the critical organs. Thus, the residual tumor is treated with radiotherapy.
  Heavy ion (carbon ion) radiotherapy was initiated at the National Institute of Radiological Sciences in 1994. Carbon ions have a high relative biological effectiveness (RBE) and a favorable dose distribution compared with other ion species and photons. Therefore, carbon ion radiotherapy has shown promising results for radioresistant tumors. Between May 1995 and January 2012, a total of 50 patients with skull base or paracervical chordomas have been treated with carbon ion radiotherapy.
  This paper describes our efforts to estimate the outcome of carbon ion radiotherapy for patients with skull base and paracervical chordomas.

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  Although Craniopharyngiomas are histologically benign, the resulting clinical sequelae can be severe because of their proximity to the critical surrounding structures. Stereotactic radiosurgery (SRS) has been emerging as a valuable adjuvant therapy for residual or recurrent craniopharyngiomas. This retrospective study aims to provide an overview of the long-term results of modern SRS for craniopharyngiomas.
  A total of 51 consecutive patients with residual or recurrent craniopharyngiomas underwent SRS consistently using Gamma Knife Model C or Perfexion from August 2002 to December 2012. The median age was 44 years and 30 men and 21 women were included in the study. Of those, 6 patients had undergone prior radiotherapy. The median tumor volume was 1.0 ml (range, 0.1-13.9) and there were 25 solid, 16 cystic and 14 mixed-type tumors. The median prescription dose delivered to the tumor margin was 12Gy (range, 10-18). Median maximal dose to the anterior visual pathways was 9.6Gy. Overall survival and local and remote recurrence rates were analyzed.
  The median follow-up time was 71 months (range, 1-144). The overall survival rate after SRS was 92% at 5 years. Local control failure occurred in 16 tumors and the 3- and 5-year local control rates were 88% and 67%, respectively. Remote recurrence occurred in 6 patients and the 5-year remote recurrence rate was 11%. The 3- and 5-year progression-free survival rates were 80% and 63%, respectively. 18 patients (35%) needed subsequent interventions. Six patients suffered aggravated visual functions owing to tumor progression after SRS but none of the patients developed radiation induced optic neuropathy. Two patients developed new-onset diabetes insipidus. Multivariate analysis showed that prior radiotherapy and tumors with a cystic component were the predictive factors for a higher rate of local recurrence.
  The present study suggested that Gamma Knife SRS could provide acceptable control of recurrent or residual craniopharyngiomas with low complication profiles in long-term follow-up.

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  Resection of large acoustic tumors is challenging due to adhesion between the tumor and adjacent tissues such as brainstem and facial nerve, and higher rate of hypervascularity.
  The authors report a case of large and hypervascular acoustic tumor who was successfully treated by combination of intravascular embolization of the feeding pial arteries and scheduled two-stage resection.
  A 31-year old man with known neurofibromatosis 2 (bilateral acoustic tumors ; resection for the right side 13 years ago) admitted to our hospital with progressing gait disturbance with left cerebellar sign and multiple cranial nerve deficits (left VI and bilateral VIIIs) due to the large recurrent left acoustic tumor which had been partially removed one year ago, because of excessive bleeding from the tumor. Preoperative magnetic resonance images demonstrated the tumor of 7 cm in diameter severely compressing to the brainstem and angiography revealed feeding arteries from the basilar artery and an intratumoral arteriovenous shunt. He underwent intravascular embolization of the feeders using N-butyl cyanoacrylate (NBCA) followed by scheduled two-stage resection.
  Postoperative course was uneventful and the symptoms partially improved to walk. Staged surgery with combination of preoperative embolization may be a treatment of choice for large hypervascular acoustic tumors.

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  Dropped head syndrome is a rare symptom with inability of horizontal gaze or gait disturbance, resulting in a chin-on-chest deformity in the standing or sitting position. In past reports, dropped head syndrome may be caused by various disease.
  The authors present two cases of dropped head syndrome with progressing cervical myelopathy undergone by anterior and posterior combined cervical fixation. In the first case, a 70-year-old female was admitted with the chief complaint of a several-year history of progressing neck stooping in the standing position and numbness of limbs. In the second case, a 83-year-old female was admitted with a 9-month history of progressing spontaneous neck hanging and neck pain in standing position. She suffered from disturbance of hand skill movement 4 months before admission. Cervical X-ray of these cases revealed dynamic instability of the C4-5 vertebra. The authors determined to undergo surgery of anterior and posterior combined cervical fixation for both patients. In both patients, postoperative course was uneventful and recurrence of dropped head syndrome has not been detected during 9 and 3 months of follow-up.
  Recently, some surgical cases of dropped head syndrome have been reported. The authors review literature of these cases and discuss surgical therapeutics of dropped head syndrome. Suitable surgery with preoperative deliberate consideration and postoperative close observation should be done for each cases with dropped head syndrome.

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