Gliomatosis cerebri (GC) is a rare glial neoplasm that is universally fatal. Although similar to glioblastoma multiforme, GC is notable among primary tumors because of diffuse, noncontiguous, often bilateral infiltration of malignant glial cells into multiple lobes of the brain, with general preservation of neuronal architecture.
Pediatric GC is substantially less common than adult GC: Only 3 cases had been reported in the literature before Peter C. Phillips, MD, and colleagues from the Children's Hospital of Philadelphia reported a 12-case series in 2006. Dr. Phillips, who is Chief of the Division of Neuro-Oncology at Children's Hospital of Philadelphia and Schoemaker Professor of Neuro-Oncology at the University Pennsylvania School of Medicine, discussed with Medscape current issues in GC, including the emerging consensus that adult and pediatric GC are fundamentally different diseases.
Stalking an Elusive Cancer
Medscape: What do we know about GC?
Dr. Phillips: Pediatric GC appears to be more a syndrome than a clearly defined entity. We have clinical observations,neuroimaging, and laboratory studies,but GC still lacks clear boundaries and definitions.
In fact, some neuropathologists doubt that it is possible to make an antemortem diagnosis of GC based on a biopsy. The histopathological features don't have a high degree of interobserver reliability. Changes include perineuronal satellitosis (cells lining up around nerve cells) and changes within the cortex that can develop into Scherer secondary structures.
Medscape: What are the implications of these changes?
Dr. Phillips: In 1940, Scherer described the appearance and behavior of glioma cells migrating away from the main tumor mass through the brain parenchyma. These patterns of glioma cell infiltration are the secondary structures of Scherer. The glioma cells migrate through the normal parenchyma, collect just below the pial margin (subpial spread), surround neurons and vessels (perineuronal and perivascular satellitosis), and migrate through the white matter tracks (intrafacicular spread). This may reflect the glial cell's reacquisition of primitive migratory behavior, leading to the spread of individual tumor cells diffusely over long distances and into disparate brain regions. The widespread involvement of near-normal-looking astrocytes has led some neuropathologists to conclude that accurate diagnosis cannot be made without histopathologic study of the entire brain.
Medscape: What is the current working definition of GC?
Dr. Phillips: GC is a diffuse neoplastic process of glial cells that infiltrate the brain. It differs from diffuse oligodendroglioma or diffuse fibrillary astrocytoma in the extent of radiographic involvement. In GC we often see bilateral thalamic or deep central radiographic abnormalities that are not contiguous.
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Cite this: Pediatric Gliomatosis Cerebri: A Ghost in the Brain - Medscape - Mar 30, 2012.