Gi-Taek Yee

A understanding of the temporal stem.

OBJECTIVE There has been inconsistency about definition of the temporal stem despite of several descriptions demonstrating its microanatomy using fiber dissection and/or diffusion tensor tractography. This study was designed to clarify three dimensional configurations of the temporal stem. METHODS The fronto-temporal regions of several formalin-fixed human cerebral hemispheres were dissected under an operating microscope using the fiber dissection technique. The consecutive coronal cuts of the dissected specimens were made to define the relationships of white matter tracts comprising the temporal stem and the subcortical gray matters (thalamus, caudate nucleus, amygdala) with inferior limiting (circular) sulcus of insula. RESULTS The inferior limiting sulcus of insula, limen insulae, medial sylvian groove, and caudate nucleus/amygdala were more appropriate anatomical structures than the roof/dorso-lateral wall of the temporal horn and lateral geniculate body which were used to describe previously for delineating the temporal stem. The particular space located inside the line connecting the inferior limiting sulcus of insula, limen insulae, medial sylvian groove/amygdala, and tail of caudate nucleus could be documented. This space included the extreme capsule, uncinate fasciculus, inferior occipito-frontal fasciculus, anterior commissure, ansa peduncularis, and inferior thalamic peduncle including optic radiations, whereas the stria terminalis, cingulum, fimbria, and inferior longitudinal fiber of the temporal lobe were not passing through this space. Also, this continued posteriorly along the caudate nucleus and limiting sulcus of the insula. CONCLUSION The temporal stem is white matter fibers passing through a particular space of the temporal lobe located inside the line connecting the inferior limiting sulcus of insula, limen insulae, medial sylvian groove/amygdala, and tail of caudate nucleus. The three dimensional configurations of the temporal stem are expected to give the very useful anatomical and surgical insights in the temporal lobe.

Central core of the cerebrum

OBJECT The purpose of this study was to understand 3D relationships of white matter fibers and subcortical areas of gray matter in the central core. METHODS The lateral and medial aspects of 4 cerebral hemispheres were dissected, applying the fiber dissection technique under the microscope. RESULTS The central core between the insula and midline includes the extreme, external, and internal capsules; claustrum; putamen; globus pallidus; caudate nucleus; amygdala; diencephalon; substantia innominata; fornix; anterior commissure; mammillothalamic tract; fasciculus retroflexus; thalamic peduncles, including optic and auditory radiations; ansa peduncularis; thalamic fasciculus; and lenticular fasciculus. It is attached to the remainder of the cerebral hemisphere by the cerebral isthmus, which is composed of white matter fibers located between the dorsolateral margin of the caudate nucleus and the full circumference of the circular sulcus of insula. The rostral fibers of the corpus callosum are included in the frontal portion of the cerebral isthmus. CONCLUSIONS It is very useful for neurosurgeons to facilitate the understanding of spatial relationships and pertinent surgical approaches in and around the central core with a highly complex anatomy by using fiber dissection.

An intracranial malignant solitary fibrous tumor.

Intracranial malignant solitary fibrous tumor (SFT) is very rare. It was identified in a 39‐year‐old female patient who underwent malignant transformation over 6 months. MRI revealed an 8 × 5 × 6 cm mass with heterogenous strong enhancement in the left occipital lobe. Histologic findings and immunophenotype (positive for CD34, bcl‐2 and vimentin, and negative for epithelial membrane antigen or S100 protein) of the primary tumor were typical of SFT. However, there was a focal area (<10% of tumor volume) showing hypercellularity, nuclear pleomorphism and increased Ki‐67 labeling index (LI) of 10% (average, 1%). At the second operation, the recurrent tumor revealed full‐blown histologic features of malignant SFT, such as infiltrative brain invasion, marked nuclear pleomorphism, frequent mitotic figures (15/10 high power fields), and high Ki‐67 LI (25%). The presence of atypical histologic finding or increased Ki‐67 LI in the typical SFT, although it is focal, needs to be mentioned in the diagnosis and also may require more aggressive surgical management.

Spontaneous regression of an unruptured and non-giant intracranial aneurysm.

It is well known that spontaneous thrombosis in giant cerebral aneurysm is common. However, spontaneous obliteration of a non-giant and unruptured cerebral aneurysm has been reported to be rare and its pathogenic mechanism is not clear. We describe a case with rare vascular phenomenon and review the relevant literatures.

Cortical Laminar Necrosis in an Infant with Severe Traumatic Brain Injury

Cortical laminar necrosis appears as hyperinense lesions with a laminar pattern on T1 weighted magnetic resonance (MR) imaging, without signs of hemorrhage or calcification on T2 weighted MR imaging or computed tomography. It has been reported to be associated with hypoxia, metabolic disturbances, drugs, and infections. We present a 12 month-old male infant who suffered diffuse brain injuries following car accident and showed laminar necrosis of cortex.

Kissing aneurysms of the distal anterior cerebral artery.

Kissing aneurysms, a particular type of multiple aneurysm are rare. A kissing aneurysms was identified at the distal anterior cerebral artery (ACA) in a 59-year-old male patient diagnosed with subarachnoid hemorrhage (SAH). The use of three-dimensional intracranial CT angiograms revealed that kissing aneurysms (that is, an aneurysm with a bilateral symmetrical mirror image) were located at the distal ACA and diffuse SAH in basal, sylvian, and interhemispheric cisterns. Both conventional carotid angiograms showed that both distal ACA aneurysms were seen separately on both internal carotid angiograms. Two aneurysms were observed simultaneously on carotid compression of either side. Some particular cautions required in diagnosing and treating kissing aneurysms are discussed, together with a literature review.

Large cystic glioblastoma multiforme.

Glioblastoma multiforme (GBM) is invariably fatal and the median survival time is approximately 12 months despite therapeutic advances. It has been reported that several clinical factors including younger age, female gender, higher preoperative Karnofsky performance score (Kps), gross total resection, long progression-free period, radiotherapy and adjuvant chemotherapy are associated with long-term survival [1]. Molecular markers and histopathology appear to be correlated with survival [2]. The presence of noncontrast-enhancing tumor, decreased edema, absence of multifocality and presence of cysts may be associated with favorable outcomes [3]. However, there are only a few reports about the relationship between cystic GBM and long-term survival [3–5]. This article reports the case of a patient with a large cystic GBM who survived over 7 years without progression and review the relevant literatures. Case Report