Axial T1-weighted postcontrast (image 1) and coronal T2-weig | Figure 1

CincyKidsRad

Cincinnati Children's Radiology

Axial T1-weighted postcontrast (image 1) and coronal T2-weighted (image 2) MRI of the brain shows a heterogeneous mass (arrow) in the right superior cerebellum abutting the undersurface of the right tentorium. At biopsy, this was confirmed to represent a pilocytic astrocytoma. The differential diagnosis for posterior fossa tumors in a child includes medulloblastoma, juvenile pilocytic astrocytoma, hemangioblastoma, and ependymoma. Throughout pilocytic astrocytoma is a WHO grade 1 tumor. It most commonly appears as a cyst with a mural nodule arising from the cerebellum and midline. Hemispheric pilocytic astrocytomas are less common in children but occur more frequently in adults. #FridayQuizDay #FridayQuiz

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Axial T1 (image 1) and T1 postcontrast (image 2) show a poorly enhancing solid mass of the posterior fossa. The location and appearance are typical of a medulloblastoma. Medulloblastoma represents the second most common pediatric brain tumor after juvenile pilocytic astrocytoma. They arise from the roof of the fourth ventricle. Other posterior fossa masses include ependymoma, pilocytic astrocytoma, and atypical teratoid/rhabdoid tumors. #FridayQuizDay #FridayQuiz](https://app.figure1.com/case-detail/0d4e8421-65e3-4eb1-a28f-c7ec81d31e5f)

Sagittal T1 weighted postcontrast (image 1) and axial T2-weighted (Image 2) MRI shows an expansile mass (arrow) of the cervical spinal cord consistent with an astrocytoma. The mass has a solid (arrow) and cystic (arrowhead) component. Children with a spinal cord tumor may present in a delayed fashion with symptoms of back pain, progressive motor weakness, progressive scoliosis, gait disturbance, and muscle rigidity. Astrocytomas are the most common spinal cord tumor in children followed by ependymomas. #NeuroWednesday](https://app.figure1.com/case-detail/0e727006-47f9-4d5d-82ab-6a6ce0d1c8c9)

Sagittal T2 weighted (image 1), sagittal T1-weighted postcontrast (image 2), and axial T2 (image 3) MRI of the cervical spine shows a large expansile pilocytic astrocytoma arising from the cervical spinal cord. Pilocytic astrocytoma is the most common spinal cord tumor in children. They most commonly occur in the thoracic portion of the spinal cord causing fusiform enlargement.](https://app.figure1.com/case-detail/132f6aa4-eaa2-45dd-9e67-0901850ad391)

5 year old with sudden onset aphasia. 4x6cm tumor invading cerebellum. Pathology pending.](https://app.figure1.com/case-detail/3556236d-3949-4a2a-89b2-545ca377f488)