Ajay Garg

Background: Primary central nervous system vasculitis (PCNSV) is a rare inflammatory vasculopathy with diverse clinical and radiological manifestations that often delay diagnosis. Although abnormalities on magnetic resonance imaging (MRI), including susceptibility-weighted imaging (SWI), fluid-attenuated inversion recovery (FLAIR), and contrast-enhanced imaging, are increasingly recognized, a characteristic imaging pattern that may facilitate diagnosis has not yet been described. We aimed to evaluate cerebellar tonsillar hemorrhages (CTH) as a potential imaging marker of PCNSV. Methods: We conducted a retrospective observational study at a tertiary neuroscience referral center in India. The discovery cohort included 51 patients with biopsy-proven PCNSV and 44 hypertensive microangiopathy controls who underwent MRI between 2018 and 2024. The imaging findings were independently reviewed for CTH and associated enhancement patterns. The reproducibility of this imaging pattern was subsequently assessed in an independent replication cohort of 55 patients with digital subtraction angiography (DSA)-proven PCNSV, evaluated between 2018 and 2026. Results: CTH were identified in 35/51 (68.6%) biopsy-proven PCNSV patients compared with 9/44 (20.4%) hypertensive controls (p<0.001). In the biopsy-proven discovery cohort, CTH demonstrated a sensitivity of 68.6% (95% confidence interval [CI], 54.1–80.9%) and specificity of 79.5% (95% CI, 64.7–90.2%) for distinguishing PCNSV from hypertensive microangiopathy and remained associated with PCNSV after adjustment for age and sex (adjusted odds ratio [OR] 12.52, 95% CI 3.46–56.94). This association persisted in exploratory age-restricted sensitivity analyses. Associated punctate or linear contrast enhancement was present in 33/35 (94.3%) CTH-positive biopsy-proven patients and was not observed in hypertensive controls with available contrast-enhanced MRI (0/4). In the independent DSA-proven replication cohort, CTH were observed in 41/55 (74.5%) patients, of whom 23/39 (58.9%) demonstrated associated cerebellar tonsillar enhancement on contrast-enhanced MRI. Interobserver agreement for CTH detection was high in the combined discovery cohort (Cohen’s κ = 0.94) and the DSA-proven replication cohort (κ = 0.91). CTH frequently occurred in the absence of clinical ataxia or diffuse brainstem involvement. Conclusion: CTH represent a frequent and reproducible imaging finding in both biopsy-proven and DSA-proven PCNSV. The presence of CTH, particularly when accompanied by punctate or linear enhancement, may improve the radiological suspicion of PCNSV and help distinguish inflammatory microangiopathy from hypertensive small-vessel disease.

Introduction: Vogt-Koyanagi-Harada (VKH) syndrome is an idiopathic immune-related disorder that affects multiple organ systems, particularly targeting melanocytes in the uvea, ear, and meninges. It can sometimes present as subacute vision loss and or headache without other systemic features mimicking optic neuritis or Idiopathic intracranial hypertension, leading to an initial misdiagnosis. Case Report: A 36-year-old male presented with an acute onset and progressive diminution of vision in both eyes for 5 days. Fundus examination revealed papillitis. Brain MRI and CSF examination were normal. Serum NMO and MOG were negative. Considering bilateral optic neuritis, he was started on intravenous methylprednisolone therapy, following which his vision showed initial improvement, followed by deterioration after 3 days. The MRI was reviewed again and showed a subtle FLAIR hyperintensity just lateral to the optic nerve entry in the posterior pole, suggestive of choroidal thickening. Optical coherence tomography showed bilateral large Neurosensory retinal detachment and intraretinal fluid. Fundus fluorescein angiography showed multifocal pinpoint hyperfluorescent spots due to leakage from the retinal pigment epithelium and dye pooling in the subretinal space, suggestive of VKH syndrome. Visual acuity improved after 3 cycles of plasma exchange to 6/6 in the right eye and 6/12 in the left eye. Conclusion: VKH should be considered in the differential diagnosis of any patient presenting with a history and examination suggestive of bilateral seronegative optic neuritis, even in the absence of characteristic extraocular manifestations of the disease.

Spinal muscular atrophy (SMA) research has focused predominantly on paediatric populations, with limited adult data from low‐ and middle‐income countries (LMICs). We prospectively recruited suspected SMA patients (age ≥ 12 years) into a neuromuscular disease cohort at a tertiary centre in northern India, using phenotyping, creatine kinase, electrophysiology and genetic testing. Forty genetically confirmed patients were included (median age 20.5 years; mean symptom duration 14.7 ± 10.9 years). Proximal lower‐limb weakness was the commonest presentation (82.5%). Forty‐five percent were misdiagnosed as muscular dystrophy or congenital myopathy. Three SMA patients received risdiplam. Our cohort highlights the diagnostic challenges of adult SMA and supports a genetics‐first approach. Early genetic confirmation shortens diagnostic delay, reduces misclassification and helps eligible patients benefit as disease‐modifying therapies become more affordable in resource‐limited settings.

BACKGROUND: Thyroid-stimulating hormone (TSH)–secreting pituitary adenomas (TSHomas) are rare lesions that result in secondary hyperthyroidism. MR elastography (MRE) is an emerging imaging modality capable of assessing the mechanical properties of tissues, offering valuable insights into tumor consistency for improved preoperative planning and resection. OBSERVATIONS: A 16-year-old female diagnosed with a giant TSHoma underwent endoscopic transnasal transsphenoidal excision. The mechanical properties of TSHoma were assessed using preoperative MRE and in vitro nanoindentation on excised specimen. Collagen content was also evaluated. Based on its appearance on MRE, a neuroradiologist predicted the tumor would be soft, and it was found to be soft during the surgery. Interestingly, the in vitro shear storage and loss moduli closely match the in vivo findings. Additionally, the tumor tissue has up to 20% collagen content in intratumoral areas. LESSONS: MRE is a reliable and clinically valuable tool for preoperative evaluation of tumor consistency in rare TSHomas. The strong concordance between MRE findings, intraoperative texture, and in vitro mechanical measurements underscores the potential of MRE to guide surgical planning, reduce operative complexity, and improve clinical outcomes, especially in uncommon and challenging cases. https://thejns.org/doi/10.3171/CASE25402