Journal of neurosurgery. Case lessons最新文献

Background: Extramedullary plasmacytomas (EMPs) are rare plasma cell tumors forming outside the bone marrow. EMPs spread to soft tissues with a predilection for the head and neck region. Therefore, EMPs are rarely included in the differential for peripheral nerve sheath tumors (PNSTs). The authors discuss a case of tibial nerve sheath invasion by an EMP in the context of multiple myeloma (MM).

Observations: A 70-year-old female with MM presented with right leg pain and a suspected PNST of the tibial nerve. Imaging revealed a T1-hypointense lesion in the popliteal fossa. Resection was attempted, but frozen pathology revealed a plasma cell neoplasm with a high Ki-67 proliferation rate. The resection was halted due to the tumor's infiltrative and hemorrhagic nature and its extensive encasement of the tibial nerve. Postoperatively, the patient received 5 fractions of radiation therapy and three courses of teclistamab, which she continued as an outpatient without complications.

Lessons: This case highlights a rare occurrence of peripheral nerve invasion by an EMP with the first documented involvement of the tibial nerve. This report suggests that EMPs should be considered in the differential diagnosis of PNSTs, particularly in MM patients. The present case underscores the need for intraoperative biopsies in PNST resection, as imaging features alone may not be fully diagnostic. https://thejns.org/doi/10.3171/CASE25104.

Background: Myxopapillary ependymomas (MPEs) are rare intradural extramedullary tumors that often involve the conus and cauda equina. Current guidelines recommend resection as first-line management, but, despite a 92.4% overall 10-year survival rate, MPEs often have a high potential for postoperative morbidity with persisting or worsened neurological function. While several studies have identified potential radiological prognostic factors, none have specifically explored their relation to neurological outcomes.

Observations: The authors retrospectively reviewed 16 MPE cases surgically treated within their institution between 2010 and 2021, evaluating preoperative/postoperative clinical data, surgical variables, and preoperative radiological features. Univariable analysis was performed using ANOVA for continuous variables and the chi-square test for categorical variables across neurological outcome groups. Multivariable modeling of neurological outcomes was done using logistic regression utilizing only radiological variables with a p value < 0.2. None of the radiological predictors reached statistical significance. The presence of preoperative weakness was the only significant predictor of a good neurological outcome within this model, while conus involvement was a significant predictor of urinary dysfunction at the final follow-up.

Lessons: Tumor size, conus involvement, and preoperative weakness are prognostic factors that may affect the morbidity profile of patients following resection. https://thejns.org/doi/10.3171/CASE25392.

Background: The infraoptic origin of the anterior cerebral artery (ACA) is a rare anatomical variant with implications for endovascular and microsurgical intervention. To date, there have been approximately 55 reported cases in the literature. Of these, only 20 are bilateral. The authors present the case of a 55-year-old female with bilateral infraoptic origin of the ACA with an associated aneurysm that developed over the course of 10 years.

Observations: On cerebral angiography, the bilateral ACAs originated from the cavernous/ophthalmic segment of the internal cerebral artery. The A1 segment was hypoplastic on both sides. The right infraoptic ACA was associated with an aneurysm, while the left had an infundibulum.

Lessons: Patients with infraoptic ACA may be at risk for developing aneurysms de novo due to turbulent flow from the morphological changes to the vessel and therefore should be considered for interval follow-up with serial imaging. Additionally, preoperative recognition of this variant is critical in order to understand the aberrant anatomy and avoid any inadvertent vascular complications. https://thejns.org/doi/10.3171/CASE25676.

Background: Recently, the distribution of subparaneurial ganglion cysts involving the common peroneal and tibial nerves was described based on MRI analysis. Crossover in extreme cases was observed at the sciatic bifurcation through a mechanism comparable to a geyser, enabled by fenestrations in the epi- and paraneurium at the level of the bifurcation. The goal of this study was to investigate whether the geyser theory for crossover holds for other locations.

Observations: The authors' prospectively maintained database of > 1100 cases of intraneural ganglion cysts in the world's literature was queried for the existence of subparaneurial ganglion cysts at locations other than the knee. A previously unrecognized case involving the ulnar nerve originating from the elbow joint was found. Reinterpretation of the patient's MRI studies showed circumferential subparaneurial distribution of a cyst over a long distance. Based on their previously reported geyser theory, the authors wondered if crossover had occurred at the level of the medial cord. A fenestration in the epi- and paraneurium at this level was confirmed on histological analysis of a normal cadaveric specimen.

Lessons: This illustrative case shows that the geyser theory also holds in other locations. Surgical treatment of these subparaneurial cysts still follows the principles of the unified articular theory. https://thejns.org/doi/10.3171/CASE25671.

Background: Plasma cell neoplasms can present as solitary plasmacytomas or multiple myeloma. Osseous solitary plasmacytomas commonly affect the axial skeleton and are treated with radiation therapy; surgery is needed as an adjunct to address instability or progressive neurological symptoms. Traditional open spinal fixation poses risks of increased infection and wound dehiscence. Minimally invasive surgery may minimize these challenges and limit delays in definitive radiation therapy.

Observations: A 61-year-old male presented with chronic low back pain with intermittent shooting pain along the S1 distribution to the bilateral lower extremities. MRI revealed a large, expansile sacral mass causing severe spinal canal stenosis, and CT demonstrated marked bony destruction. Biopsy confirmed plasma cell neoplasm. Because of his progressive instability, the patient underwent minimally invasive spinopelvic fixation using augmented reality (AR) guidance, with dual S2-alar-iliac screws for stabilization. Postoperatively, he received intensity-modulated radiation therapy, 4500 cGy, 180 cGy per fraction in 25 fractions per day for a month. Imaging at 5 months demonstrated unchanged bony erosion, stable instrumentation, and symptom improvement.

Lessons: Progressive pain due to instability in patients with osseous solitary plasmacytoma may necessitate surgical stabilization. Minimally invasive AR-guided lumbopelvic fixation offers an effective stabilization strategy, minimizing postoperative recovery and time to definitive therapy. https://thejns.org/doi/10.3171/CASE25634.

Background: Human herpesvirus 6 (HHV-6) is a neurotropic virus known to induce encephalitis in immunocompromised patients as well as a subset of pediatric patients. However, ventriculitis secondary to HHV-6 is a rare occurrence among immunocompetent adults. Although acquired hydrocephalus has been described to infrequently co-occur with HHV-6 encephalitis in pediatric and immunocompromised adult patients, it has not been described in an immunocompetent adult.

Observations: The authors present a rare case of HHV-6 encephalitis and obstructive hydrocephalus in an immunocompetent adult patient. Despite CSF diversion, the emergence and proliferation of multiple septations throughout the ventricular system resulted in the progression of severe hydrocephalus.

Lessons: Previous studies have linked HHV-6 to inflammatory states, occurring predominantly among children and immunocompromised adults, that manifest primarily as meningitis and encephalitis. This case highlights the fact that HHV-6 can cause life-threatening ventriculitis and hydrocephalus in immunocompetent adults. Pathophysiological mechanisms of virus-induced neuroinflammation yielding intraventricular septation formation are reviewed. https://thejns.org/doi/10.3171/CASE25273.

Background: Early intracerebral hematoma (ICH) expansion without aneurysm rerupture is extremely rare in patients with a ruptured basilar artery perforator aneurysm (BAPA), and the treatment strategy has not been established.

Observations: A 47-year-old male was rushed to the authors' hospital due to loss of consciousness. CT imaging showed diffuse subarachnoid hemorrhage (SAH) and ventriculomegaly, and 3D CT angiography (CTA) showed a BAPA. Ventricular drainage was performed, and conservative treatment for the BAPA was started. However, CT imaging on SAH day 1 showed an enlarged ICH in the right temporal lobe with no increase of SAH. Subsequent CTA showed no contrast extravasation from the right middle cerebral artery and no detection of BAPA. Since the BAPA was not considered to have reruptured and there was no mass effect due to the ICH, conservative treatment was continued with close imaging studies. There was no rerupture of the BAPA, and ventriculoperitoneal shunt insertion was performed on SAH day 36. The patient was transferred to a rehabilitation hospital on SAH day 62 with a modified Rankin Scale score of 1 (mild attention disorder).

Lessons: Conservative management for a ruptured BAPA can be performed even in a case of early ICH enlargement without aneurysm rerupture. https://thejns.org/doi/10.3171/CASE25760.

Background: Intraoperative shunt use during carotid endarterectomy (CEA), although critical for cerebral protection, may cause internal carotid artery (ICA) dissection in approximately 0.5% of cases. Shunt-induced dissections represent a distinct pathophysiological mechanism, differing from surgical technique-related dissection, and typically occur distal to the arteriotomy site due to trauma from shunt tips or balloon inflation.

Observations: The authors present 2 cases of ICA dissection occurring during CEA with shunt use, both successfully managed with emergency endovascular stent insertion. In both case, complete resolution was achieved, with modified Rankin Scale scores of 0. Case 1 involved a 70-year-old male with 95% right carotid stenosis who developed dissection extending 6 cm distal to the arteriotomy. Dual-stent carotid artery stent placement resulted in complete resolution. Case 2 involved an 80-year-old female who developed extensive 55-mm left internal carotid dissection, immediately treated with overlapping dual-stent placement. A literature review of 13 cases demonstrated favorable outcomes with recent endovascular management approaches.

Lessons: Shunt-related dissection is a preventable complication requiring specific technical precautions, including ensuring symmetric balloon expansion, using a gentle insertion technique, and minimizing longitudinal movement. When dissection occurs, immediate endovascular stent placement may provide superior outcomes compared with conservative management, effectively preventing thromboembolic complications while achieving excellent functional recovery. https://thejns.org/doi/10.3171/CASE25697.

Background: Basilar artery occlusion (BAO) is a threatening condition requiring rapid reperfusion to preserve brainstem function. Although endovascular thrombectomy is considered standard treatment, underlying pathology or limited resources may require surgical intervention. The authors performed an emergency superficial temporal artery-superior cerebellar artery (STA-SCA) bypass in the hyperacute setting of BAO following elective aneurysm surgery. The bypass prevented stroke progression and dramatically improved consciousness.

Lessons: This case demonstrates that with early recognition, protocolized monitoring, and microsurgical capability, STA-SCA bypass is a viable effective strategy for revascularization in acute posterior circulation stroke and can prevent progression of the ischemic core.

Observations: A 69-year-old man with a recent history of bilateral cerebellar infarction underwent elective microsurgical clipping of a left M1 middle cerebral artery aneurysm. The authors confirmed complete aneurysm exclusion with postoperative CTA. Eight hours later, the patient developed aphasia and deep state coma. CTA perfusion revealed BAO, with extensive cerebellar penumbra and a small core. Due to severe preexisting right vertebral and basilar intracranial atherosclerotic disease, urgent STA-SCA bypass was performed with a right subtemporal approach. Intraoperative studies confirmed graft patency reperfusion. The patient recovered consciousness and was discharged with a modified Rankin Scale score of 3. https://thejns.org/doi/10.3171/CASE25710.

Background: Dural sealants, widely used in neurosurgical practice, have been associated with few complications, mostly relating to the expansive nature of the hydrogel. Although generally well tolerated, DuraSeal expands up to 150% after application, and rare reports have described complications from mass effect.

Observations: This report presents the case of a 34-year-old female with a past surgical history of multiple operations for a Chiari type 1 malformation. After a thorough workup, intraoperative images and histological findings revealed a concealed hematoma-like mass at the patient's previous surgical site, likely due to the DuraSeal system. Imaging revealed that the DuraSeal was mostly hyperintense on T2-weighted MRI with focal spots of hypo-/isointensity, similar in appearance to an abscess or hematoma. Histological analysis showed exuberant fibrosis, granulation tissue, and a granulomatous response to the foreign material used for the dural patch and seal rather than the wall of an infectious abscess.

Lessons: This case adds to the growing body of literature on DuraSeal, highlighting the imaging and histological characteristics of "dural sealant-omas" and their expansile nature that can lead to the formation of a mass mimicking an abscess or a hematoma. In areas susceptible to compression, clinicians ought to be vigilant to identify findings consistent with the appearance of these dural sealant-omas. https://thejns.org/doi/10.3171/CASE25574.