Related Experiment Video
Updated: Aug 6, 2026
08:57
Identifying, Diagnosing, and Grading Malignant Peripheral Nerve Sheath Tumors in Genetically Engineered Mouse Models
Published on: May 17, 2024
Primitive neuroectodermal tumor of the leptomeninges
M Fujii1, T Orita, T Nishizaki
1Department of Neurosurgery, Yamaguchi University School of Medicine, Ube, Japan.
Neuroradiology
|January 1, 1991
Summary
Primitive neuroectodermal tumor (PNET) is rarely found without a clear brain mass, instead spreading diffusely within the subarachnoid space. This case highlights its unusual presentation and discusses CT and MR imaging features.
Area of Science:
- Neuro-oncology
- Radiology
- Pathology
Background:
- Primitive neuroectodermal tumors (PNETs) are rare malignant brain tumors.
- PNETs typically present as intraparenchymal mass lesions.
- Diffuse subarachnoid spread of PNET without an obvious intraparenchymal mass is exceptionally uncommon.
Observation:
- This report details an unusual case of PNET.
- The tumor exhibited diffuse spread within the subarachnoid space.
- No obvious intraparenchymal mass lesion was identified.
Findings:
- Computed tomography (CT) and magnetic resonance (MR) imaging features were analyzed.
- The imaging characteristics of this rare PNET presentation are discussed.
- Diagnostic challenges associated with atypical PNET morphology are highlighted.
Implications:
- This case expands the understanding of PNET presentation.
- Radiologists and oncologists should consider PNET in the differential diagnosis of diffuse leptomeningeal disease.
- Accurate imaging interpretation is crucial for timely diagnosis and treatment planning in rare neurological conditions.
Related Concept Videos
01:30Neurulation
Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three primary cell layers of the embryo: ectoderm, mesoderm, and endoderm. In humans, the majority of this system is formed via primary neurulation, in which the central portion of the ectoderm—originally appearing as a flat sheet of cells—folds upwards and inwards, sealing off to form a hollow neural tube. As development proceeds, the anterior...
01:19Encephalitis l: Introduction
Encephalitis is inflammation of the brain parenchyma, most often due to infections or autoimmune processes. It presents with neuropsychiatric features such as fever, altered mental status, behavioral changes, cognitive dysfunction, seizures, focal deficits, and sometimes autonomic instability. In some cases, the meninges are also involved, resulting in meningoencephalitis.Infectious CausesInfectious encephalitis is most commonly viral but can also result from bacterial, fungal, or parasitic...