An onset of cervical myelopathy due to ossification of the posterior atlantoaxial membrane (PAAM) is extremely rare in older patients, and its clinical characteristics are still unclear. We report an onset of ossification of PAAM with congenital atlas hypoplasia in an 81-year-old man who presented with a 2-year history of progressive cervical myelopathy. Cervical computed tomography (CT) revealed canal stenosis secondary to a hypoplastic posterior arch of the atlas with a diameter of 20.3 mm between the anterior and posterior process. Magnetic resonance imaging showed marked spinal cord compression at the level of C1–2 secondary to atlas hypoplasia as well as ossification of PAAM. The patient underwent laminectomy of C1 and partial C2, as well as removal of the ossification, without atlantoaxial fusion. His neurological status improved 1 year postoperatively. In older patients, cervical myelopathy secondary to PAAM ossification, in the absence of trauma and atlantoaxial instability, may be induced by age-related pathophysiology associated with congenital atlas hypoplasia.

Cerebral hyperperfusion syndrome (CHS) is a potentially devastating complication of carotid endarterectomy (CEA). Early detection and treatment of hyperperfusion are important before the condition develops into CHS. We herein present a case involving a 65-year-old female with severe right internal carotid artery (ICA) stenosis, who experienced hyperperfusion after right CEA. During the postoperative course, changes in the resting cerebral blood flow (rCBF) were evaluated using single-photon emission computed tomography (SPECT), and were found to correlate with the changes in the signal intensity of cortical arteries, cortical veins, and perilateral ventricular veins of the right middle cerebral artery (MCA) territory on susceptibility-weighted imaging (SWI). SWI showed a prominent hyperintensity of cortical arteries in the right MCA territory at postoperative day 1 (POD1), but the hyperintensity gradually decreased over time and became indistinct by POD48. As for cortical veins and perilateral ventricular veins, SWI showed an increased signal intensity of these veins during the peak of rCBF on POD1, but later, the signal intensity decreased as rCBF decreased on POD5. The signal intensity of cortical veins and perilateral ventricular veins finally returned to normal on POD9. Those SWI findings could be related to an impairment of cerebral autoregulation and the resulting hyperperfusion. SWI could be potentially useful as an additional tool in the evaluation of hyperperfusion.

Spinal epidural hematoma (SEDH) is an uncommon pathology. Here, we report a case of SEDH with recurrences, along with a literature review of relevant cases to identify characteristics of SEDH recurrence. A 13-year-old girl experienced sudden-onset of back pain and bilateral leg weakness. She was diagnosed with a cervical idiopathic epidural hematoma, and the symptoms subsided with conservative management. Four months after the event, she again experienced back pain due to recurrence of the cervical epidural hematoma, but she was observed because no neurological deficits could be detected. Fifteen months after the initial SEDH, she experienced severe back pain and tetra-paresis due to recurrence. The SEDH was located in the left ventral and dorsal aspect at the C6–T1 level, with severe spinal cord compression. The hematoma was removed through left hemilaminectomy. Bleeding was noted from the epidural venous plexus along the left C6 spinal root, which had coagulated. After hematoma resection, her symptoms gradually improved, and she was discharged 3 weeks after surgery without any neurological deficits. No hematoma recurrence has since been experienced. Recurrent SEDH is relatively rare, with only 11 cases previously reported. Recurrent hematoma cases are more common in young, female patients, while SEDH, in general, is more common in males in their late forties. The recurrence interval is shorter in non-surgical cases than those requiring surgery. Knowledge of these characteristics may be useful in the future management of SEDH.

Symptomatic thoracic disc herniation (TDH) with thoracic radiculopathy alone is an extremely rare condition. Here, we report a rare case of TDH in a 52-year-old man who presented with medically refractory severe right flank pain. Based on pain distribution, pain intensity changes according to truncal position, ineffectiveness of intercostal nerve block, and radiological findings, his pain was determined to be caused by TDH at T9-10 level. Symptomatic TDH often requires invasive surgery. However, TDH with radiculopathy alone can be treated via a posterior approach without spinal cord manipulation or spinal fusion. We could eliminate the pain by removing TDH with hemilaminectomy and microdiscectomy using an O-arm-based navigation system.

The patient was a 48-year-old female recreational triathlete who had been experiencing mild low back pain since high school. She had recently developed right leg pain and had gradually worsening difficulty in running. She preferred to undergo spinal surgery without fusion so that she could return to triathlons as soon as possible, and she was referred to our hospital. Plain radiographs showed Meyerding grade 3 isthmic spondylolisthesis at L5 and a slipped L5 vertebral body. Selective nerve root block at L5 relieved the right leg pain temporarily. The final diagnosis was right L5 radiculopathy due to compression by the ragged edge of the L5 pars defect from the posterior side and by the upside-down foraminal stenosis at L5–S1. An L4–L5 partial laminectomy was performed with resection of the ragged edge and one-third of the caudal pedicle at L5. Adequate decompression was achieved by exposing the L5 spinal nerve root from the branch portion to the outside of the L5 pedicle. The right leg pain disappeared postoperatively and she returned to participating in triathlons. One year after surgery, there was slight radiographic progression of the slip in 5 mm; however, there had been no recurrence of the right leg pain. Several studies have reported excellent outcomes after decompression surgery in patients with isthmic spondylolisthesis. To our knowledge, this is the first report of successful lumbar decompression surgery without fusion for high-grade isthmic spondylolisthesis in a triathlete, although in short-term results.

Back pain and lower extremity pain have various causes and occasionally occur simultaneously, creating diagnostic difficulties. In addition, athletes require special consideration in terms of treatment. Here, we report a case of foraminal stenosis as a result of lumbar disc prolapse combined with facet hypertrophy contralateral to the dominant hand in a baseball pitcher that was successfully treated by minimally invasive full-endoscopic surgery. A 31-year-old left-handed male baseball pitcher presented with complaints of low back pain and right buttock pain while pitching. A diagnosis of foraminal stenosis caused by a disc bulge combined with facet hypertrophy contralateral to the dominant hand was made on the basis of physical and radiological findings. His symptoms improved immediately after transforaminal full-endoscopic lumbar discectomy and foraminoplasty under local anesthesia. He returned to play 3 months after surgery. Foraminal stenosis due to facet hypertrophy may occur in the side contralateral to the throwing arm in pitchers. Minimally invasive decompression using a full-endoscopic procedure is required for high-level athletes at this position.

Although lumbar spondylolysis (LS) is regarded as a stress fracture, the underlying pathomechanism has yet to be fully elucidated. Here, we present a case that casts doubt on the notion that LS is truly a stress fracture. An 11-year-old female basketball player was brought to our clinic with a 2-week history of persistent low back pain. Magnetic resonance imaging with short TI inversion recovery (STIR-MRI) showed high signal intensity changes at the L4 pedicles bilaterally. Computed tomography (CT) revealed a faint fracture line at the left pars interarticularis. We made a diagnosis of stress fracture and recommended conservative treatment, including cessation of sports activities and wearing of a hard brace. Compliance with treatment was excellent. As expected, the STIR-MRI findings at L4 gradually resolved and bone healing was achieved. However, a follow-up STIR-MRI scan 10 weeks later revealed high signal intensity at the left L5 pedicle. Conservative treatment was continued for the findings at L5, which were considered to indicate a stress fracture (spondylolysis). Five weeks later, CT revealed a bony defect in the lamina at L5 on the left and bone union at L4. Although LS is generally considered to be a stress fracture, there have been several reports of familial occurrence and genetic predisposition. This patient’s mother had also been treated for spondylolysis at L5. These observations suggest an underlying genetic etiology in this case.

Fenestration of the supraclinoid internal carotid artery (ICA) is extremely rare and may occasionally be associated with saccular aneurysms; nevertheless, the natural history remains unclear. The authors reviewed the cases of fenestration of the supraclinoid ICA and evaluated the clinical characteristics and angioarchitecture with particular focus on the incidence for aneurysm development and rupture. Previously reported 24 cases and 1 new case from our institute were examined for the presence of aneurysms (including size and presence of bleb) leading to subsequent subarachnoid hemorrhage (SAH). Furthermore, 16 cases with sufficient information were classified into one of the three types according to the developmental condition of fenestration and fusion site: Type A (developed fenestration in which the ICA appears to duplicate [two cases]); Type B (hypoplastic fenestration fused to the ICA at the origin of the posterior communicating artery [Pcom] [six cases]); and Type C (hypoplastic fenestration fused to the Pcom itself or appeared to be a duplicated Pcom [eight cases]). In type A, the two cases had an aneurysm (100%), one of which caused SAH (50%). In type B, all six cases had an aneurysm (100%), and one of five led to SAH (20%) (one case lacked information regarding SAH). In type C, five of the eight cases had an aneurysm (62.5%), with no SAH (0%). The result suggested that the extent of development of fenestration and the location of fusion are related to the incidence of aneurysms and risk for rupture.

Extramammary Paget’s disease (EMPD) is a rare form of neoplasm. Metastasis of EMPD to locations other than lymph nodes and intra-epithelial regions is rare; there are a limited number of case reports of metastases to the liver, lung, bone, and brain. We present a rare case of EMPD that metastasized to the brain and was treated with surgical resection. A 66-year-old man presented with a small palpable mass in the scrotum. After 5 years of observation, he was diagnosed with EMPD that metastasized to the lymph nodes and lung. Tumor resection and postoperative chemotherapy were performed. Six months after the last chemotherapy treatment, he presented with a right temporal lobe tumor and underwent surgical resection. Histopathological analysis revealed brain metastasis of EMPD. Three months after surgery, magnetic resonance imaging (MRI) showed local tumor recurrence, and intensity modulated radiation therapy (IMRT) (45 Gy/15 Fr) was performed. Although the metastatic brain tumor was well controlled, the primary tumor progressed. He was provided best supportive care and died 5 months after brain tumor resection. In this report, we present a rare case of brain metastasis of EMPD, treated with surgical resection, and histopathologically confirmed to be metastatic EMPD.

We describe a rare case of 42-year-old female who had possible double crush syndrome caused by iatrogenic spinal epidermoid tumor (ET) associated with lumbar puncture as well as concomitant sacral Tarlov cyst in close proximity. She presented with progressive left-sided perianal pain. She had a history of a Caesarean section with lumbar spinal anesthesia. Magnetic resonance imaging (MRI) demonstrated a relatively small intradural extramedullary solid lesion at L5/S1 level and cystic lesion at S2 level. We considered there were two different lesions, such as a tumor and Tarlov cyst; however, we could not rule out the possibility of a single lesion with two different components. Furthermore, there was a distinct compression at more than one locations along the course of the left S2 nerve root and we suspected possible double crush syndrome. We conducted tumor removal and the lesion turned out to be two different pathologies, such as an ET and Tarlov cyst. Both lesions were intraopertively pinching the left S2 nerve root at different sites as expected. The tumor was successfully removed and the cyst wall was imbricated and sutured. We need to take the possibility of ET into consideration if the patient underwent invasive spinal procedure previously. We also have to pay attention to the possibility of double crush syndrome if the nerve root possibly holding the responsibility for symptoms is compressed at two or more sites. This is the first report of possible double crush syndrome caused by acquired spinal tumor and congenital Tarlov cyst.

Isolated hypoglossal nerve palsy (IHP), or hypoglossal nerve palsy without any other neurological signs, is rare. We report a woman with atlantoaxial dislocation (AAD) who presented with IHP due to hypoglossal nerve compression by an osteophyte at the hypoglossal canal. A 77-year-old woman presented with speech difficulties and the feeling of a swollen tongue on the left side for 3 days. Her only neurological feature was left hypoglossal nerve palsy. She had been diagnosed with AAD 2 years before. Computed tomography (CT) and high-resolution magnetic resonance imaging (MRI) revealed the compression of the basicranial hypoglossal nerve at the external orifice of the hypoglossal canal by an AAD osteophyte which was causing IHP. IHP can develop due to hypoglossal nerve compression by an osteophyte from AAD. CT and high-resolution MRI revealed this rare mechanism of IHP.

A 6-year-old female was incidentally found to have a brain tumor. Magnetic resonance imaging (MRI) demonstrated a gadolinium-enhanced mass in the left parietal lobe. We performed gross total resection with the assistance of fluorescent guidance by 5-aminolevulinic acid (5-ALA). A histological examination of the tumor specimen showed well-differentiated astroblastic features with focal anaplasia. Fluorescence in situ hybridization (FISH) revealed meningioma 1 (MN1) gene alteration and supported our diagnosis. She received local radiotherapy and oral temozolomide followed by maintenance temozolomide chemotherapy, and the tumor was well controlled without any neurological deficit for 27 months. Our case is considered to be valuable since it describes a patient who is diagnosed to have a well-differentiated astroblastoma with both focal anaplastic features and MN1 gene rearrangement. A larger study is warranted to establish evidence supporting the diagnosis and treatment of astroblastoma with molecular characteristic features. MN1 alteration will be a diagnostic marker for astroblastoma in the future.

A 39-year-old man had received boron neutron capture therapy (BNCT) for a grade II astrocytoma (compatible with diffuse astrocytoma, not otherwise specified in the WHO 2016 criteria). He returned to his previous work after surgery, but, 7 years later, he suddenly developed seizures, and his health condition deteriorated. Therefore, he underwent a second surgery. The mass removed in the second operation was mostly necrotic as a result of previous radiation treatment. He then showed no signs of recurrence and did not require any treatment other than antiepileptic drugs for 25 years. He was able to be employed by a listed company until the age of 65 years for light jobs as a physically handicapped individual. This case suggests the effectiveness of BNCT even for rather low-grade astrocytomas.

We report a case of post-traumatic syringomyelia (PTS), which developed 2 months after spinal cord injury (SCI). A 20-year-old man who was involved in a motorcycle accident sustained a complete SCI resulting from a burst fracture of the T5 vertebral body. He underwent posterior fixation with decompression at another hospital 2 days after the injury. Postoperative imaging suggested that spinal stenosis endured at the T4 level and swelling of the spinal cord above that level. Two months later, he felt dysesthetic pain in his forearms and hands, but the cause of the pain was not examined in detail. Four months after the injury, he presented with motor weakness in the upper extremities. Magnetic resonance imaging (MRI) showed syringomyelia ascending from the T3 level to the C1 level, and he was referred to our hospital immediately. The imaging studies suggested that PTS was caused by congestion of the cerebrospinal fluid (CSF) at the T3 level. The patient was treated with syringosubarachnoid (SS) shunt at the T1-T2 level, whereby neurological symptoms of the upper extremities were immediately relieved. Postoperative MRI showed shrinkage of the syrinx. At the latest follow-up 2 years postoperatively, there was no sign of recurrence. It is noteworthy that PTS potentially occurs in the early phase after severe SCI. We discuss relevant pathology and surgical treatment through a review of previous literature.

Cerebral hyperperfusion syndrome (HPS) is a rare complication of carotid endarterectomy (CEA) and stenting. There are only a few case reports about HPS after intracranial stenting, and its clinical course remains unclear. We report an unusual case of HPS after intracranial internal carotid artery (ICA) stenting. An 87-year-old woman underwent uneventful balloon angioplasty for the right intracranial ICA one year ago; then she presented with restenosis at the same arterial location. She then underwent an ICA stent placement procedure. Preoperative cerebral blood flow (CBF) studies revealed hemodynamic ischemia. At the time of surgery, the stenotic lesion was near-occlusion. Twelve hours after the successful stenting procedure, the patient became restless, and near-infrared spectroscopy (NIRS) indicated a blood flow increase to the affected side. Arterial spin labeling (ASL) imaging performed on the same day showed high signal intensity only in the right hemisphere. She was treated with sedation, blood pressure control, and minocycline hydrochloride administration. Because of the strict management under continuous monitoring with NIRS, her symptoms gradually improved over the next 6 days. The right-to-left difference observed with ASL imaging resolved 6 days after surgery, and she was discharged with no neurological deficit. This case highlights the utility of NIRS monitoring in the management of HPS after intracranial stenting.

A case in which metallic embolism was suspected after carotid artery stenting (CAS) is described. A 79-year-old woman was referred to our hospital because of a severe stenosis of the left cervical internal carotid artery (ICA). Carotid ultrasound revealed that the plaque was fibrous and was accompanied with partial calcification. The carotid stenosis was treated by CAS. The magnetic resonance imaging (MRI) taken in the following day of the CAS demonstrated that a new abnormal spot at the left frontal lobe. The spot appeared as a signal void on T1, T2, diffusion, susceptibility-weighted image (SWI), and fluid attenuated inversion recovery (FLAIR) image, and was surrounded by a high-signal halo on T2 and diffusion-weighted images (DWIs). The spot also demonstrated “blooming” appearance on SWIs. Despite the lesion she was asymptomatic all through the postoperative course, and she left our hospital on postoperative day 6. Follow-up MRI obtained 27 months after the CAS demonstrated that the lesion remained at the left frontal lobe without any signal changes. The patient remained asymptomatic at the last follow-up. Considering the location of the new abnormal spot (in the vascular territory of the catheterized vessel), these imaging characteristics and asymptomatic clinical course, the spot likely suggested metallic embolism. This is the first case in which the metallic embolism was suspected after CAS.

Meningioma en plaque (MEP) often needs invasive surgery to resect totally because of its widespread proliferation along the dura mater. We report a minimally invasive surgical technique for non-brain-exposure exoscopic and endoscopic volume reduction in an elderly patient with MEP. An 83-year-old woman presented with gait disturbance and cognitive dysfunction that had progressed over 6 months. Magnetic resonance imaging (MRI) revealed a large MEP on the right frontal lobe with peritumoral edema. On confirming the benign nature of the tumor (WHO grade 1) by biopsy, the main feeders and tumor were transarterially embolized. Volume reduction surgery was performed under the assistance of an exoscope and an endoscope while being careful not to expose and damage the cortex. Her symptoms completely resolved postoperatively. This surgical technique without exposing the brain may be a treatment choice for elderly patients with benign symptomatic convexity MEP.