TUMORS Flashcards
Classification of astrocytoma
diffuse well-differentiated astrocytoma (grade II), anaplastic astrocytoma (grade ill), and glioblastoma (glioblastoma multiforme, or “GBM,” grade N
The grade I classification for astrocytomas is reserved for the relatively benign group that includes
pilocytic astrocytomas (well-differentiated tumors mostly of children and young adults); the pleomorphic xanthoastrocytoma (with lipid-filled cells), and the subependymal giant cell astrocytoma (associated with tuberous sclerosis).
The ependymomas are subdivided into
cellular, myxopapillary, clear cell, and mixed types
a “tumor-like formation that has its basis in maldevelopment”
hamartoma
indicate all tumors composed of primitive-looking cells,
blastoma
Because of this capacity to transform the cellular genome, the virus product is called an ____; such oncogenes are capable of immortalizing, so to speak, the stimulated cell to form a tumor.
oncogene
mutations in the genes that code for i________ are common in gliomas and oligodendrogliomas and their presence relates to less tumor progression
socitrate dehydrogenase(IDH1 and 2)
____ have combined deletions in chromosomes 1p and 19q respond well to chemotherapy and this property increases survival
oligodendrogliomas
in approximately 50 percent of gliomas there is an overexpression or a mutant form of ______ and of _____, suggesting a role for these in the progression of certain tumor types
epidermal growth factor receptor (EGFR) plateletderived transforming growth factor receptor (PDGFR)
alters sensitivity of the glioma to chemotherapy
MGMT, a methyltransferase
These high-grade gliomas account for approximately 20 percent of all intracranial tumors and for more than 80 percent of gliomas of the cerebral hemispheres in adults.
G l i o b l a sto m a M u ltifo r m e a n d A n a p l a stic Ast rocyto m a
extraneural mets of GBM
bone and lymph nodes
gross findings of GBM
variegated appearance, being a mottled gray, red, orange, or brown, depending on the degree of necrosis and presence of hemorrhage, recent or old.
histology of GBM
The characteristic histologic findings of glioblastoma are hypercellularity with pleomorphism of cells and nuclear atypia; identifiable astrocytes with fibrils in combination with primitive forms in many cases;
This ______ appearance distinguishes glioblastoma from the anaplastic astrocytomas, which show frequent mitoses and atypical cytogenic features but no grossly _____
variegated necrotic or hemorrhagic areas
The vasculature and fibroblasts of glioma can undergo a sarcomatous transformation giving the tumor a mixed appearance that is termed ____
gliosarcoma
More recently, the progression of astrocytomas and oligodendrogliomas to more malignant forms has been related to ____
the enzyme isocitrate dehydrogenase, encoded by the genes IDH1 and IDH2
natural hx of untreated glioblastima
Fewer than 20 percent of patients survive for 1 year after the onset of symptoms and only about 10 percent live beyond 2 years
how to give TMZ
The drug is administered daily (75 mg/m2) concurrently with radiotherapy and, after a hiatus of 4 weeks, given for 5 d every 28 d for 6 cycles.
high levels of a methyltransferase protein (MGMT) in some glioblastomas lead to_______
resistance to chemotherapy
________have been developed in response to the upregulation of EGFR
Tyrosine kinase inhibitors (erlotinib, gefitinib)
Almost all glioblastomas recur within _____ of their original site and 10 percent develop additional lesions at distant locations.
2 em
Antiangiogenic agents such as________ a VEGF inhibitor, sometimes given in combination with chemotherapy, may delay progression and greatly reduce cerebral edema, therefore diminishing the requirement for corticosteroids, but also do not prolong survival
bevacizumab,
_____ is a slowly growing tumor of infiltrative character with a tendency in some cases to form large cavities or pseudocysts
Cerebral astrocytoma
