Toddler with left arm weakness

CT and MRI of supratentorial primitive neuroectodermal tumor
Axial CT without contrast of the brain (above left) shows an ill-defined large heterogenous right periventricular mass causing midline shift to the left. Axial T2 (above right) and T1 MRI without contrast (below left) of the brain show the mass to be fairly well circumscribed, primarily solid with some cystic components, and to show heterogenous enhancement on axial T1 MRI with contrast (below right).

The diagnosis was primitive neuroectodermal tumor.

School ager with increasing headaches

MRI of gliomatosis cerebri
Three contiguous axial FLAIR MRI images (above left, above right, below left) show a high signal intensity infiltrative mass without much mass effect centered in the left frontal lobe which crosses the corpus callosum into the right front lobe and right central white matter. Axial T1 MRI with contrast of the brain (below right) shows the mass to have faint enhancement.

The diagnosis was gliomatosis cerebri due to anaplastic astrocytoma.

Teenager with papilledema and vision loss

MRI of supratentorial ependymoma
Axial (above left) and coronal (above right) T1 MRI without contrast of the brain show a right hemispheric high signal intensity mass with mural nodules that is causing some mass effect to the left. The mass was also of high signal intensity on T2 MRI. Axial (below left) and coronal (below right) T1 MRI with contrast of the brain show enhancement of the mural nodules.

The diagnosis was ependymoma.

Infant with febrile seizure

CT and MRI of desmoplastic infantile glioma
Axial (above left) and coronal (above right) CT without contrast of the brain show a mass in the left temporal lobe that medially has a higher density solid component and laterally has a lower density cystic component. The mass is surrounded by low density vasogenic edema and is causing some midline shift to the right. Axial (below left) and coronal (below right) T1 MRI with contrast of the brain show homogenous contrast enhancement of the solid portion of the mass.

The diagnosis was desmoplastic infantile ganglioglioma.

Toddler with an infected neck mass

CT of fourth branchial cleft cyst
Coronal (above left), sagittal (above right) and axial (below) CT with contrast of the neck degraded by motion artifact shows a round, low density mass in the neck inferior to the hyoid bone and anterior to the thyroid gland that is just to the left of midline that has rim enhancement. Endoscopy subsequently showed a tract to the left pyriform sinus.

The diagnosis was fourth branchial cleft cyst.

Teenager with progressive spasticity

CT of os odontoideum
Sagittal CT without contrast of the cervical spine (left) shows a large well-corticated ossicle posterior and superior to the anterior arch of C1 and superior to the dens, hypertrophy of the anterior arch of C1, and a large atlanto-dens interval due to atlanto-axial dislocation. Sagittal T2 MRI without contrast of the cervical spine (right) shows a narrow spinal canal secondary to the atlanto axial dislocation with spinal cord compression and abnormal bright signal in the spinal cord at C1-C2.

The diagnosis was dystopic os odontoideum.