History and Physical
A 6-year-old previously healthy boy presented with a 20-day history of increasing headache, nausea, and vomiting upon awakening from sleep. He was admitted to the pediatric emergency unit with worsening double vision, gait disturbance, and back pain over two days. He was the only child of healthy, nonconsanguineous parents.
On physical examination, temperature was 36.3°C, pulse 100, respiratory rate 24/min, blood pressure 100/60, weight 19 kg (25%), height 114 cm (37%). On neurological examination, he was conscious and cooperative, with no signs of meningeal irritation. Papilledema was present on fundoscopy. Horizontal nystagmus was detected when looking to the left. Dysmetria, dysdiadochokinesia, and ataxic gait were also noted. Examination of other systems was unremarkable.
Diagnostic Workup
Routine laboratory tests were normal.
Head CT showed a hyperdense rounded mass in the fourth ventricle with obstructive hydrocephalus.
Brain MRI with contrast showed corresponding contrast enhancement and diffusion restriction, with leptomeningeal metastases in the brain ( Fig. 42.1 ) and spine ( Fig. 42.2 ).
Group 3 medulloblastoma with intracranial leptomeningeal metastasis. (A) Noncontrast head CT shows expansile, hyperdense mass in the fourth ventricle ( white arrows ). Brain MRI, (B) axial T2 demonstrates tumor isointense to cerebellar gray matter. (C) Sagittal T1 shows tumor compression of cerebellum and dorsal brainstem. (D) Axial DWI image shows prominent restricted diffusion. Axial postcontrast T1 shows (E) mild homogeneous tumor enhancement ( arrow ) and (F) left parietal nodular leptomeningeal metastasis ( arrow ). DWI , Diffusion-weighted imaging.
Group 3 medulloblastoma with spinal leptomeningeal metastasis. Lumbar spine MRI, (A) sagittal postcontrast T1 shows enhancing drop metastases along the distal spinal cord ( black arrows ) and thecal sac ( white arrow ). (B) Axial T2 demonstrates a large intradural metastasis ( white arrows ) compressing and displacing the spinal cord anteriorly ( black arrow ).
