Adult Brainstem Gliomas With H3K27M Mutation: Radiology, Pathology, and Prognosis.

Adult brainstem gliomas are difficult to classify based on radiologic and histologic features. A K27M mutation in histone 3 has been described to identify high-grade midline gliomas associated with a particularly unfavorable prognosis. While initially considered a pediatric entity, it is now known that H3K27M-mutant brainstem gliomas occur in all age groups, but they are less well understood in adults. We studied clinical, radiologic, and pathologic features of 25 brainstem gliomas diagnosed at our institution between 1994 and 2017 in subjects at least 18 years old. Seven tumors (28%) were positive for the H3K27M mutation, and their median overall survival was significantly shorter than in the H3-wildtype group (p = 0.004). Although the mutation was invariably associated with a poor prognosis, our study also illustrates the radiologic and pathologic heterogeneity in this molecular tumor subtype. The results showed that H3K27M-mutant status and clinically aggressive course cannot be ruled out based on low-grade histology on the initial biopsy, exophytic growth, only focal or minimal enhancement or an extrapontine location, such as midbrain or medulla. These results favor an integrated approach employing a combination of clinical, radiologic, histologic features as well as H3K27M immunohistochemistry for the diagnostic subclassification of adult brainstem gliomas.

A rare adult cause of dizziness.

A 55-year-old man was seen with progressively worsening dizziness over 10 months. The initial assessment with unremarkable laboratory and imaging studies suggested a peripheral vestibular disorder. He was then lost to follow-up but later was seen with worsening ataxia. Additional imaging studies showed subtle parenchymal lesions in the posterior fossa. The differential diagnoses included nutritional deficiencies, autoimmune disorders, systemic malignancies, and intracranial tumors. The final diagnosis was confirmed by a biopsy.

Comparison of image quality in pediatric head computed tomography reconstructed using blended iterative reconstruction versus filtered back projection.

We compared image quality in 44 pediatric head computed tomographic exams reconstructed using four levels of blended iterative techniques (iDOSE 1-4) versus filtered back projection. Three radiologists reviewed the 220 series in a randomized, blinded manner. They scored each series based on gray-white matter differentiation, visibility of the pre-pontine cistern, caudate head, image noise, and image quality. Noise was measured in the vitreous and the thalamus. Composite scores were highest with iDOSE 4 (P<.0001). Interobserver agreement was fair to moderate. Spearman's rho of the vitreous (-0.62, P<.001) and thalamus (-0.58, P<.001) confirmed a significant inverse correlation between iDOSE level and noise.

Clinical course in Parkinson's disease with elevated homocysteine.

Elevated homocysteine (Hcy), prevalent in Parkinson's disease (PD), is potentially a modifiable risk factor for neurologic deterioration. We measured cognitive, affective and motor changes over 2 years in a cohort of people with early PD. Subjects whose Hcy had been elevated (>14 micromol/L, n = 31) at baseline were compared with the rest (n = 66). Overall progression in 2 years did not significantly differ (p = 0.20). Four subjects with elevated and one with normal Hcy had died (p = 0.03). We conclude that hyperhomocysteinemia does not predict significantly worse progression over 2 years in early PD. The data raised the possibility of higher mortality, but the number of deaths was small.