Gliomas astrocytomas

Malignant gliomas (astrocytomas) are lethal invasive brain tumors. Invasive cell migration is initiated by extension of pseudopodia into interstitial spaces. In a DIGE technology study (see above), pseudopodia of glioma cells were harvested and their protein profile compared with the profile of whole cells. Increased pseudopodial constituents were identified as actin,... 

A number of toxic conditions beside hypoosmotic stress and hypoxia/ischemia produce brain edema and the causes may be related to regulation of the aquaporins (see Ch. 34). AQP1 and AQP4 are intensely upregulated in reactive astrocytes in subarachnoid hemorrhage [69], in human glioma and astrocytoma [70] and AQP4 in endothelia and reactive astrocytes in metastatic carcinoma [71,72]. 

Fischer U, Heckel D, Michel A, Janka M, Hulsebos T, Meese E (1997) Cloning of a novel transcription factor-like gene amplified in human glioma including astrocytoma grade I. Hum Mol Genet 6 1817-1822... 

Brain lesion analysis is also an active area of research. DTI metrics have been found to help differentiate between tumor types and promises to provide a sensitive method for abnormal tissue characterization. Fractional anisotropy has already been found to correlate with the cell density of brain tumors (Beppu et al., 2003 Beppu et al., 2005). The ability of FA to correlate with cell density likely accounts for the sensitivity of FA to tissue typing in brain lesions. Fractional anisotropy has been found to differentiate between low grade and anaplastic astrocytomas, to help differentiate between brain metastasis and high grade gliomas, and there is evidence that FA may help to detect tumor infiltration not visible by conventional MRI (Holmes et al., 2004 Tsuchiya et al., 2005 Goebell et al., 2006). Other DTI metrics have been utilized in brain lesion analysis and the early findings point to the breadth of future possibilities. 

Glial tissue "Benign" gliomas Glioblastoma multiforme, astrocytoma... 

Astrocytomas are among the most fibrillar of CNS neoplasms, more fibrillar than other gliomas except tany-cytic ependymomas and subependymomas (see Table... 

The oligoastrocytoma is a mixed glioma composed of both astrocytoma and oligodendroglioma, as described in the respective sections on these tumors (see Fig. 20.10A). Much less common than oligoastrocytoma, mixed gliomas may have a component of ependymoma. ... 

All have some cells that meet cytologic criteria of astrocytoma (long cellular processes, GFAP, elongated nuclei). They often will have additional cells that resemble other types of gliomas. 

Neurofibroma may occur as a sporadic tumor or as part of the dominantly inherited tumor syndrome called von Recklinghausen disease or neurofibromatosis-1 (NF-l).i Plexiform neurofibromas are multiple swollen fascicles that are associated with NF-1. Other nervous system signs of NF-1 are more than one neurofibroma, optic nerve glioma (more appropriately called optic nerve pilocytic astrocytoma), and malignant peripheral nerve sheath tumor with glandular or rhabdomyoblastic regions. ... 

Because the hemangioblastoma is nonfibrillar, it should not resemble an astrocytoma. However, the resemblance may occur for two reasons sampling and artifact. Cerebellar hemangioblastomas are often cystic, with the actual neoplasm embedded somewhere in the wall of the cyst as a mural nodule. Biopsy specimens of the cyst wall may show conspicuously GFAP-positive gliosis (see the Gliosis versus Glioma section later in this chapter). 

---