Enlarging neurenteric cyst at the craniocervical junction with a fluid-fluid level on magnetic resonance imaging: illustrative case.

BACKGROUND: Neurenteric cysts are relatively rare benign congenital intracranial cystic lesions that enlarge rarely and very slowly. The authors present a case of an enlarging neurenteric cyst at the craniocervical junction with a fluid-fluid level on magnetic resonance imaging (MRI). OBSERVATIONS: A 34-year-old man with no significant medical history underwent head MRI to investigate mild headaches. An incidental cystic lesion, approximately 8 mm in diameter, was revealed at the craniocervical junction. Serial follow-up MRI showed cyst enlargement with a fluid-fluid level. Four years later, the cyst reached a size of 15 mm and was surgically removed. The cyst contained cloudy fluid with a high protein concentration, without any bleeding or tissue fragments. Pathological examination confirmed the diagnosis of a neurenteric cyst. The patient recovered well, was discharged home, and has remained recurrence free for 2 years. LESSONS: The growth dynamics of the relatively rapidly expanding neurenteric cyst at the craniocervical junction were monitored over time using MRI. This cyst exhibited the distinctive feature of a fluid-fluid level as it enlarged. Investigating the mechanisms underlying fluid-fluid level formation may offer novel insights into the pathogenesis of cyst enlargement. https://thejns.org/doi/10.3171/CASE24180.

Significance of upper cervical epidural venous engorgement on head computed tomography in the initial diagnosis of spontaneous intracranial hypotension: patient series.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a rare condition characterized by positional headache, for which contrast-enhanced magnetic resonance imaging (MRI) is the preferred diagnostic method. Although MRI reveals characteristic findings, head computed tomography (CT) is usually the first diagnostic step, but identifying features of SIH on CT is often difficult. This study was specifically designed to evaluate the utility of head CT in detecting upper cervical epidural venous engorgement as a sign of SIH. OBSERVATIONS: Of 24 patients with SIH diagnosed between March 2011 and May 2023, 10 did not undergo upper cervical CT. In the remaining 14 patients, engorgement of the upper cervical epidural venous plexus was observed. CT detection rates were consistent with MRI for spinal fluid accumulation or dural thickening. After treatment, in 92.9% of patients, the thickness of the epidural venous plexus decreased statistically significantly from 4.8 ± 1.3 mm to 3.6 ± 1.2 mm. LESSONS: This study suggests that upper cervical spine CT focused on epidural venous engorgement may be helpful in the initial diagnosis of SIH and may complement conventional MRI evaluation. Extending CT imaging to the upper cervical spine will improve the diagnostic accuracy of patients with positional headaches suspected to be SIH.

Spontaneous resorption of a convexity arachnoid cyst associated with intracystic hemorrhage and subdural hematoma: A case report.

Background: Intracranial arachnoid cysts (ACs) are developmental anomalies usually filled with cerebrospinal fluid (CSF), rarely resolving throughout life. Here, we present a case of an AC with intracystic hemorrhage and subdural hematoma (SDH) that developed after a minor head injury before gradually disappearing. Neuroimaging demonstrated specific changes from hematoma formation to AC disappearance over time. The mechanisms of this condition are discussed based on imaging data. Case Description: An 18-year-old man was admitted to our hospital with a head injury caused by a traffic accident. On arrival, he was conscious with a mild headache. Computed tomography (CT) revealed no intracranial hemorrhages or skull fractures but an AC was seen in the left convexity. One month later, follow-up CT scans showed an intracystic hemorrhage. Subsequently, an SDH appeared then both the intracystic hemorrhage and SDH gradually shrank, with the AC disappearing spontaneously. The AC was considered to have disappeared, along with the spontaneous SDH resorption. Conclusion: We present a rare case where neuroimaging demonstrated spontaneous resorption of an AC combined with intracystic hemorrhage and SDH over time, which may provide new insights into the nature of adult ACs.

De novo formation of twig-like middle cerebral artery: An illustrative case.

Background: Twig-like middle cerebral artery (T-MCA) is a rare vascular abnormality characterized by the replacement of the M1 segment of the middle cerebral artery (MCA) with a plexiform arterial network of small vessels. T-MCA is generally regarded as an embryological persistence. Conversely, T-MCA may also be a secondary sequela but no reports of cases of de novo formation exist. Here, we report the first case describing possible de novo T-MCA formation. Case Description: A 41-year-old woman was referred to our hospital from a nearby clinic because of transient left hemiparesis. Magnetic resonance (MR) imaging revealed mild stenosis of the bilateral MCAs. The patient then underwent MR imaging follow-ups once a year. MR imaging at the age of 53 showed a right M1 occlusion. Cerebral angiography revealed a right M1 occlusion and formation of a plexiform network consistent with the occlusion site, leading to the diagnosis of de novo T-MCA. Conclusion: This is the first case report describing possible de novo T-MCA formation. Although a detailed laboratory examination did not confirm the etiology, autoimmune disease was suspected to have precipitated this vascular lesion.

Nonaneurysmal subarachnoid hemorrhage associated with COVID-19 infection: A case report.

Background: Most coronavirus disease 2019 (COVID-19)-related cerebrovascular disorders are ischemic while hemorrhagic disorders are rarely reported. Among these, subarachnoid hemorrhage (SAH) is very rarely reported and nonaneurysmal SAH has been reported in only about a dozen cases. Here, we report a case of nonaneurysmal SAH as the only clinical manifestation of COVID-19 infection. In addition, we reviewed and analyzed the literature data on cases of nonaneurysmal SAH caused by COVID-19 infection. Case Description: A 50-year-old woman presented to an emergency department with a sudden headache, right hemiparesis, and consciousness disturbance. At that time, no fever or respiratory failure was observed. Laboratory data were within normal values but the rapid antigen test for COVID-19 on admission was positive, resulting in a diagnosis of COVID-19 infection. Computed tomograms (CTs) showed bilateral convexal SAH with a hematoma but three-dimensional CT angiograms showed no obvious sources, such as a cerebral aneurysm. Therefore, the patient was diagnosed with nonaneurysmal SAH associated with COVID-19 infection. With conservative treatment, consciousness level and hemiparesis both improved gradually until transfer for continued rehabilitation. Approximately 12 weeks after onset, the patient was discharged with only mild cognitive impairment. During the entire course of the disease, the headache, hemiparesis, and mild cognitive impairment due to nonaneurysmal SAH with small hematoma were the only abnormalities experienced. Conclusion: Since COVID-19 infection can cause nonaneurysmal hemorrhaging, it should be considered (even in the absence of characteristic infectious or respiratory symptoms of COVID-19) when atypical hemorrhage distribution is seen as in our case.