Bilateral decompression via a unilateral approach (BDUA) was initially described by Young et al. (4) and then was modified by McCulloch (5). In this technique, the risk of iatrogenic instability is reduced by preserving the facet joints. Unilateral stabilization and contralateral decompression were considered to be effective in terms of operation time, surgical complications, and patient benefit visual analogue scale in comparison to other surgical techniques for the treatment of lumbar spinal stenosis. There is no doubt that a fusion procedure should be performed in the presence of accompanying instability. However, in spinal stenosis cases without instability and spondylolisthesis less than grade 1, the role of spinal fusion is controversial. This is so because spinal instrumentation in degenerative spine may cause adjacent segment degeneration and disease. Therefore, procedures such as bilateral foraminotomy, BDUA, and

Intracranial dermoid tumors are extracerebral congenital cysts. Dermoid cysts have two types as intradural and extradural. Intradural dermoid cysts are originated from the intracranial cerebrospinal fluid space. However, calvarium-originated extradural lesions increase in size with a slow growth in cyst volume, but the cause of active growth is unknown. Dermoid cysts act like slow-growing cerebral tumors. Differential diagnosis includes other cysts and cystic tumors. Their radiologic appearance looks like polycystic lesions which is associated with a wide expansion in the cerebrospinal fluid areas and cause brain translocation. In the cranial tomography and magnetic resonance imaging assessment, high-cholesterol-containing dermoids demonstrate cerebrospinal fluid characteristics. The present study based on the review of central nervous system patients with highly rare dermoid localizations such as calvarial bone, temporal lobe and lateral ventricle.

Although giant cell tumor of bone has been considered as a disease with benign course, it can lead to bone destruction and serious morbidity. A 19-year-old case was presented with hip pain. There was a recurrence after 9 months of curative surgical resection and zoledronic acid use, and as surgical morbidity would be high, antiosteoclastic receptor activator of nuclear factor kappa B ligand inhibitor denosumab treatment was administered. She had a complete remission after 18 months of denosumab treatment. The important point in the present case is that it has been followed up without recurrence after around 42 months of denosumab use and 11 months of follow-up after the cessation of drug. In recurrent cases in which nonmetastatic surgery is not suitable, the use of denosumab decreases tumor progression. The duration of use in unresectable and advanced cases still remains unclear.

Retroclival epidural hematoma in adults is uncommon. Although most cases are associated with craniocervical trauma, other mechanisms have been reported, such as coagulopathy, vascular lesions, and pituitary apoplexy. We report two adults diagnosed with retroclival epidural hematoma. One patient was an 89-year-old male with leukemia and thrombocytopenia who sustained a fall and developed a traumatic retroclival epidural hematoma with brainstem compression; surgery could not be performed due to his clinical condition and he died 5 days later. The other patient was a 78-year-old female with atrial fibrillation who developed a spontaneous retroclival epidural hematoma as a result of warfarin use; she was treated conservatively with anticoagulant reversal and methylprednisolone and was subsequently discharged without neurological deficit. Retroclival hematomas are primarily treated conservatively due to the difficulty of surgical approach. The bleeding mechanism and dural and venous anatomy of this region tend to limit hematoma expansion.

Intravascular papillary endothelial hyperplasia (IPEH) also known as Masson's tumor, is a benign, slow growing, vascular lesion which is seen very rarely and only a few cases have been reported intracranially in the literature. It has been reported at many sites, but the posterior fossa involvement is very rare. The preoperative diagnosis is very difficult, as there is no enough cases to achieve a clear understanding about the details of its radiological findings. Differential diagnosis have to be made especially from angiosarcoma and meningioma. It is curable by total surgical removal. In this article we presented the characteristic clinical, radiological, perioperative and pathological findings in a case of IPEH in an unusual location, origin and behavior. To best of our knowledge, we presented the first case of IPEH originating from tentorium.