Desmoplastic infantile astrocytoma and ganglioglioma
Desmoplastic infantile astrocytoma and gangliogliomas are a rare intracranial tumor, which despite their aggressive appearances tend to have a good prognosis and are considered WHO grade I tumors.
Terminology
Previously considered separate entities, desmoplastic infantile astrocytoma and desmoplastic infantile ganglioglioma are now grouped together in the current (2016) WHO classification of CNS tumor, recognizing the clinical, radiological and pathological similarities of the two entities .
Epidemiology
The vast majority occur in children below the age of 2 years, and males are more commonly affected with a M:F ratio of approximately 1.5-2:1 . Only a handful of adult cases have been reported, again with a male predilection .
Clinical presentation
A rapidly increasing head circumference is the most common presentation, with symptoms usually presenting in a short time (5 days to 3 months) .
Seizure activity is uncommon.
Pathology
Macroscopic appearance
Desmoplastic infantile astrocytoma and gangliogliomas are typically large predominantly cystic tumors with a peripheral solid component abutting and attached to the meninges .
Microscopic appearance
These tumors are heterogeneous, with the solid peripheral desmoplastic component composed of meningeal tumor cells, primarily a mixture of fibroblast-like cells and neuroepithelial cells embedded within a connective tissue background . In both desmoplastic infantile astrocytomas and desmoplastic infantile gangliogliomas the dominant neuroepithelial component is composed of astrocytes, however, in the latter neoplastic neuronal elements are also identified .
Immunophenotype
Leptomeningeal desmoplastic component:
Neuroepithelial component:
- GFAP: positive
- neuronal markers (e.g. synaptophysin): positive if ganglion cells present
Radiographic features
Desmoplastic infantile ganglioglioma manifests as an exceptionally large cerebral hemispheric mass composed of both cystic and solid portions (usually more cystic plus a mural nodule) involving both cortex and meninges. The frontal and parietal lobes are the most common sites.
CT
The solid portion of these large masses is typically slightly hyperattenuating and usually located along the cortical margin of the mass. Following administration of contrast, these masses usually enhance intensely and may demonstrate a dural tail .
Calcification is variably reported, uncommon in some series and up to 50% in others .
MRI
The solid portions typically have the following signal intensity :
- T1: isointense to brain parenchyma
- T2: isointense to brain parenchyma
- T1 C+ (Gd)
- intense enhancement
- a dural tail may be seen
Treatment and prognosis
Surgical resection is the treatment of choice, however, because of the large size of these lesions and the firm attachment to the dura, complete resection is difficult and a significant rate of perioperative mortality can result from attempted surgical excision. If complete resection is achieved, however, excellent long-term disease-free survival can be expected .
In cases of partial resection, adjunctive chemotherapy may be considered and have been reported to produced some reduction in tumor volume .
Differential diagnosis
- embryonal tumors with multilayered rosettes
- pilocytic astrocytoma
- ependymoma
- ganglioglioma
- pleomorphic xanthoastrocytoma
Siehe auch:
Assoziationen und Differentialdiagnosen zu infantiles desmoplastisches Gangliogliom:
