Hosting 728 files, 2951 images, and 4 contributors.

Random Case

Ewing Sarcoma
Joseph Junewick, MD FACR
over 11 years ago
Enter A Workflow
Standard2   Academic2

Please choose a workflow. A standard workflow allows you to browse the repository with full case detail; the academic workflow allows you to browse the repository with limited case detail revealed. Double click on the images to launch image viewer.

ARSt Case Repository

Chiari III

Case Detail

Anatomy: Brain-Spine
Joseph Junewick, MD FACR
Diagnostic Category: Developmental or Congenital
Created: over 10 years ago
Updated: over 10 years ago
Tags: PEDS
Modality/Study Types: MR
Adobe32 PDF Imagej32 ImageJA


Newborn with suboccipital mass.

Case Images


Chiari III

Clinical Notes

Surgery – Skin covered suboccipital cystic mass confined by the dura.

Pathology – Leptomeningeal tissue with few nodular neuroglial elements.


MR – Sagittal T1 and axial and coronal T2 images demonstrate occipitocervical meningocele with dysrhaphism. Note cervicomedullary kink, tectal beak, cerebellar hypoplasia, callosal dysgenesis and ventricular dysmorphism.


Chiari III malformation is an extremely rare anomaly. The pathogenesis of malformation is not clear, however, underdistension of the embryonic ventricular system secondary to the abnormal neurulation might result in a hypoplastic posterior fossa and consequently in the caudal displacement of brain stem and cerebellum in Chiari malformations. The low occipital or skull base osseous defects and associated cephaloceles probably develop due to the failure of induction of enchondral bone by incomplete closure of neural tube, or due to the failure of ossification centers to fuse completely in Chiari III malformations.

Patients with Chiari III malformation most commonly present with a cystic mass of low occipital and/or high cervical location. The infants suffer from hydrocephalus, frequently associated with the evidence of increased intracranial pressure, within the first few months of life. The clinical findings related to the compression of cerebellum, brain stem and lower cranial nerves. The prognosis of patients is usually poor.

Chiari III malformation is characterized by the hermiation of posterior fossa contents through a low occipital or upper cervical osseous defect. Upper cervical vertebrae show an incomplete fusion of posterior arches, most commonly at the level of C1 vertebra. The patients with Chiari III malformation will also show imaging findings related to Chiari II malformation.


Cakirer S. Chiari III malformation: Varieties of MRI appearances in two patients. Clinical Imaging (2003); 27(1):1-4.

Corporate Office: 616.363.7272, 3264 North Evergreen Drive, Grand Rapids, MI 49525

Spectrum Health Helen Devos Childrens Hospital GE HealthCare