Spinal cord deformity with aggravation of tethering in saccular limited dorsal myeloschisis during the first 2 months of life.

BACKGROUND: Although the optimal timing of prophylactic untethering surgery for limited dorsal myeloschisis (LDM) with intact or subtle neurological findings diagnosed at birth remains undetermined, intentional delayed surgery is commonly used for flat and tail-like LDM. Conversely, for saccular LDM, early surgery is indicated during the postnatal period because it prevents rupture of the sac. We treated a saccular LDM patient, in whom intentional delayed surgery was selected because the sac was thickly covered with normal skin. We describe the clinical course of the case and discuss the optimal timing of the surgery. CASE DESCRIPTION: The patient had a dorsal midline sac in the upper lumbar region. Initial magnetic resonance imaging (MRI) after birth revealed a tethering tract that began at the dome of the sac and joined the lumbar cord. Dorsal bending of the cord at the stalk-cord union and invagination of the cord into the sac were noted. At 2 months, he was neurologically normal; however, the second MRI examination revealed that the cord tethering was aggravated. The cord was markedly displaced dorsally and to the left, with deviation of the cord to the sac out of the spinal canal. Following untethering surgery, the spinal cord deformity markedly improved. CONCLUSION: Early surgery may be recommended for saccular LDM when tethering is present, including dorsal bending of the cord at the stalk-cord union and invagination of the cord into the sac observed on detailed MRI examination, even if the sac has no risk of rupture.

Two Cases of Large Filar Cyst Associated with Terminal Lipoma: Relationship with Retained Medullary Cord.

BACKGROUND: A small, incidental filar cyst associated with terminal lipoma is thought to be caused by failure of secondary neurulation; however, the precise embryologic background is not fully understood. Retained medullary cord (RMC) also originates from late arrest of secondary neurulation. The central feature of RMC histopathology is a central canal-like ependyma-lined lumen with surrounding neuroglial core. CASE DESCRIPTION: We surgically treated 2 patients with a large cyst in the rostral part of the filum and lipoma in the caudal filum. At cord untethering surgery, the filum was severed at the caudal part of the cyst. Histopathologically, the filar cyst was the cystic dilatation of the central canal-like structure at the marginal part of the lipoma. The central canal-like structure was continuous caudally in the lipoma, and its size decreased toward the caudal side. CONCLUSIONS: The present findings support the idea raised by Pang et al that entities such as filar cyst, terminal lipomas, and RMC can all be considered consequences of a continuum of regression failure occurring during late secondary neurulation.

Retained medullary cord with sacral subcutaneous meningocele and congenital dermal sinus.

BACKGROUND: A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated cord-like structure extending continuously from the conus medullaris to the dural cul-de-sac that is caused by late arrest of secondary neurulation. Five patients with RMC extending to an associated sacral subcutaneous meningocele have been reported. CASE PRESENTATION: We report an additional patient with RMC, in whom a congenital dermal sinus (CDS) was found in the caudal portion of the RMC. At the age of 3 days, the patient underwent surgery consisting of meningocele excision and cord untethering, and CDS was noted histologically in the proximal cut end of the RMC. During a second surgery at the age of 5 months, after determining the exact border of the nonfunctional RMC and the true conus by neurophysiological mapping, we removed the entire length of the remnant RMC, including newly developed epidermoid cysts in the CDS. CONCLUSION: Although the exact pathoembryogenesis of concurrent RMC and CDS is unknown, an associated subcutaneous meningocele, caused by failure of primary neurulation, could be involved. Surgeons should be aware of the possibility of the coexistence of CDS when dealing with RMCs that extend out to the extradural space.

Two cases of subfrontal schwannoma, including a rare case located between the endosteal and meningeal layers of the dura.

Subfrontal schwannomas arising from the olfactory groove are rare and their origin remains uncertain because olfactory bulbs do not possess Schwann cells. We present two cases of subfrontal schwannomas treated with surgical resection. In one case, the tumor was located between the endosteal and meningeal layers of the dura mater. This rare case suggests that subfrontal schwannomas may originate from the fila olfactoria.

[A pregnant case on which EC-IC bypass was successfully performed in the acute phase of brain infarction].

A 30 year-old, 28 weeks-pregnant woman (gravida 2, para 2) suffered from a sudden onset of aphasia when she was having a chat in the upright position. Although the initial symptom soon disappeared, transient attacks of aphasia combined with weakness in the right arm occurred intermittently, particularly when she uprose. MR image disclosed a small acute infarcted focus at the genu of the left internal capsule, while MRA showed an occlusion of the intracranial portion of the left internal carotid artery. She was treated conservatively, but the transient attack continued and her consciousness was slightly lowered. Since repeated examination revealed no recanalization of the occluded artery, treatment was reinforced by using heparin and dopamine on day 1. However, her consciousness was not improved, and dopamine evoked nausea and vomiting. On day 2, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was carried out. Soon after surgery, she regained alertness and the transient attack subsided. Examinations could not clarify the course of the occlusion. She was treated with heparin until she delivered a sound baby in the 37th week. Although STA-MCA anastomosis for acute ischemic stroke is still debatable, it may be a good option even for a pregnant woman when suffering from intractable progressing stroke.

A patient with a dysembryoplastic neuroepithelial tumor who underwent epilepsy surgery after initial seizure.

BACKGROUND: Since dysembryoplastic neuroepithelial tumors (DNTs) are benign tumors that are frequently associated with long-standing medically intractable epilepsy, it is well known that the surgical strategy is resection of the associated epileptogenic zone as well as the tumor. However, the surgical strategy for DNT with a single seizure has not been fully discussed. METHODS: We report an 8-year-old boy with DNT in the nondominant frontal lobe who underwent epilepsy surgery at 3 months after his initial seizure. RESULTS: An intraoperative electrocorticogram revealed frequent paroxysmal cortical activity lateral to the tumor. Since resection of the tumor resulted in persistent paroxysmal activity in this cortex, additional resection was performed. The histological findings in the cortex revealed the presence of cortical dysplasia (CD) (Palmini type IIA). Lesionectomy alone might have left the epileptogenic CD. CONCLUSION: It is thought that epilepsy surgery should be recommended in patients with typical neuroimaging findings of DNT, even if the patients had only one episode of seizure.

Hypoxia induces de-stabilization of the LAT1 large neutral amino acid transporter mRNA in brain capillary endothelial cells.

Blood-brain barrier (BBB) transport of large neutral amino acids is mediated by the large neutral amino acid transporter type 1 (LAT1 transporter). Although the gene encoding the Glut1 glucose transporter is up-regulated in hypoxia, the response of the LAT1 gene to hypoxia is not known. The present study investigates the changes in the LAT1 mRNA in cultured bovine brain capillary endothelial cells exposed to 1% O2 for 24-48 h. The LAT1 mRNA was initially down-regulated in hypoxia with reciprocal changes in the Glut1 mRNA. No changes in the 4F2hc mRNA in hypoxia were observed. Hypoxia caused an initial de-stabilization of the LAT1 mRNA, and the t1/2 of the LAT1 mRNA in control and hypoxic cells was 6.4 +/- 0.5 and 2.4 +/- 0.1 h, respectively. To further explore post-transcriptional regulation of LAT1 gene expression, the polysome and cytosol fractions of the control and hypoxic endothelial cells were isolated, and LAT1 mRNA binding proteins were detected by ultraviolet light cross-linking. Whereas the cytosol contained no LAT1 mRNA binding proteins, the cell polysome fraction expressed several LAT1 mRNA binding proteins, including principal 40-, 70- and 80-kDa proteins. These studies are consistent with post-transcriptional de-stabilization of the LAT1 large neutral amino acid transporter in hypoxia.