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.

Differentiating Benign from Malignant Bone Tumors Using Fluid-Fluid Level Features on Magnetic Resonance Imaging

OBJECTIVE: To analyze different fluid-fluid level features between benign and malignant bone tumors on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This study was approved by the hospital ethics committee. We retrospectively analyzed 47 patients diagnosed with benign (n = 29) or malignant (n = 18) bone tumors demonstrated by biopsy/surgical resection and who showed the intratumoral fluid-fluid level on pre-surgical MRI. The maximum length of the largest fluid-fluid level and the ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane were investigated for use in distinguishing benign from malignant tumors using the Mann-Whitney U-test and a receiver operating characteristic (ROC) analysis. Fluid-fluid level was categorized by quantity (multiple vs. single fluid-fluid level) and by T1-weighted image signal pattern (high/low, low/high, and undifferentiated), and the findings were compared between the benign and malignant groups using the chi2 test. RESULTS: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of bone tumors in the sagittal plane that allowed statistically significant differentiation between benign and malignant bone tumors had an area under the ROC curve of 0.758 (95% confidence interval, 0.616-0.899). A cutoff value of 41.5% (higher value suggests a benign tumor) had sensitivity of 73% and specificity of 83%. CONCLUSION: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane may be useful to differentiate benign from malignant bone tumors.

Three Cases o Pituitary Apoplexy

Three cases of pituitary apoplexy in patients with pituitary tumors are described. This uncommon condition is characterized by the sudden onset of headache, nausea, vomiting, visual impairement, diplopia, disturbance of consciousness and autonomic or hormonal dysfunction. The diagnosis is strengthened by a radiologically abnormal pituitary fossa & clinical symptoms and confirmed by the operative findings of hemorrhage necrotic tissue. Recently, CT enables the early diagnosis of pituitary apoplexy. Since CT can detect blood, it can document acute or chronic hemorrhage in pituitary adenoma. In addition, CT can discriminate between densities other than blood and can therefore be used to diagnosis those cases of pituitary apoplexy in which infarction & necrosis predominate. Finding of acute bleeding within tumor in enlarged sellar on plain CT establishes the diagnosis of pituitary apoplexy. Following three cases of pituitary apoplexy had special findings which was fluid level with faint rim enhancement of high density of dependent portion. Conculsively We agree that CT can help the early diagnosis and prompt surgical intervention of pituitary apoplexy.