OBJECTIVE:To characterize routine magnetic resonance imaging (MRI) manifestations of molecularly defined isocitrate dehydrogenase (IDH)-mutant, 1p/19q codeleted oligodendroglioma, to introduce two newly proposed intratumoral imaging signs, assess their diagnostic efficacy, and interpret their histologic basis via voxel-wise imaging-pathology matching. MATERIALS AND METHODS:36 surgically validated oligodendrogliomas were retrospectively analyzed per the 2021 WHO CNS tumor criteria; MRI signals were correlated with histologic indices such as cellular density and myxoid microcystic change. RESULTS:The cohort comprised 24 males and 12 females with a mean age of (30.9 ± 16.1) years. All supratentorial lesions were mostly cystic-solid, showing T1-hypointense solid parts, T2/fluid-attenuated inversion recovery (FLAIR) slightly hyperintense parenchyma, T2-hyperintense cysts, and heterogeneous enhancement, predominantly WHO grade 2. No intergrade differences in baseline MRI/clinical features were found (p > 0.05). Cross-sectional prevalence: isolated ripple sign 16.7%, isolated finger-like cystic sign 8.3%, dual signs 5.6%, total positivity 30.6%. Separate κ values (0.81 and 0.83) revealed excellent inter-rater consistency; the two signs occurred independently (p > 0.05) with high specificity but low sensitivity. Histologically, the ripple sign stemmed from alternating hypercellular and microcystic grey-white matter bands, whereas finger-like cysts arose from tract-aligned fused microcysts. CONCLUSION:This glioma entity mostly presents as infiltrative supratentorial cystic-solid masses. The two novel signs serve as high-specificity auxiliary markers but lack sufficient sensitivity; large multi-center validation is warranted. Integrated MRI and pathological correlation elevate preoperative diagnostic accuracy.
BACKGROUND:Multiple system atrophy (MSA) is a progressive adult-onset synucleinopathy that remains difficult to diagnose clinically, particularly in younger patients and during early disease stages. Brainstem nuclei degeneration resulting in reduced monoamines in cerebrospinal fluid (CSF) analysis may further complicate diagnostic interpretation. OBJECTIVES:To describe a clinicopathologic case of early-onset MSA found to have decreased CSF monoamines suggestive of a primary neurotransmitter synthesis disorder. MATERIALS AND METHODS:Clinical records, neuroimaging findings, CSF neurotransmitter analysis, and postmortem neuropathologic examination were reviewed. RESULTS:A 41-year-old woman developed rapidly progressive parkinsonism, dystonia, dysphagia, and speech impairment. Broad CSF analysis was significant for reduced homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and tetrahydrobiopterin, raising concern for a monoamine synthesis defect and prompting treatment for sepiapterin reductase deficiency (SRD). Despite directed therapy, neurologic decline continued. Postmortem examination demonstrated neuropathologic findings consistent with MSA, parkinsonian subtype (MSA-P). Early cortical and allocortical amyloid-β deposition corresponding to Thal phase 2 was also identified. No additional proteinopathies were present. CONCLUSION:Degeneration of dopaminergic and serotonergic nuclei in MSA can reduce CSF monoamine metabolite levels and mimic disorders of neurotransmitter biosynthesis despite correlation with tetrahydrobiopterin levels. This case highlights a potential diagnostic pitfall when interpreting CSF neurotransmitter studies in adults with parkinsonism.
OBJECTIVE:The medial accessory olivary nucleus (MAO), a distinct but inconsistently present subnucleus of the human inferior olivary complex, is poorly characterized despite its proposed role in cerebellar motor circuitry. We aimed to investigate its structural asymmetry, functional correlates, and pathological vulnerability in humans. MATERIALS AND METHODS:We performed high-resolution histological analysis (Nissl and immunohistochemistry) in 35 neurologically normal brains to quantify MAO volume and neuronal numerical density and relate these to handedness and lifetime manual dexterity. In a separate cohort of 20 Parkinson's disease (PD) brains (Braak stages 4 - 6), we compared MAO neuronal numerical density and α-synuclein pathology to age-matched controls. RESULTS:The MAO was identifiable in 74% (26/35) of neurologically normal cases. A significant volumetric asymmetry was present (p < 0.01), with larger MAO volume contralateral to the dominant hand, and the asymmetry index correlated with lifetime manual dexterity scores (r = 0.54, p = 0.002). PD brains showed a 43% reduction in MAO neuronal numerical density versus controls (p < 0.001) and more severe α-synuclein pathology (median grade 3 vs. 0, p < 0.001). CONCLUSION:The MAO may be a neuroanatomically variable but functionally lateralized structure that appears linked to fine motor control and may exhibit selective vulnerability in PD.
