Astroblastoma
Encyclopedia
Astroblastoma is a rare, glial tumor
derived from the astroblast, a type of cell that closely resembles spongioblastoma and astrocytes. Astroblastoma cells are most likely found in the supratentorial region of the brain that houses the cerebrum, an area responsible for all voluntary movements in the body. It also occurs significantly in the frontal, parietal, and temporal regions, areas where movement, language creation, memory perception, and environmental surroundings are expressed. These tumors can be present in major brain areas not associated with the main cerebral hemispheres, including the cerebellum
, optic nerve
, cauda equina
, hypothalamus
, and brain stem
.
The most defining symptom of astroblastoma, regardless of location, is elevated intracranial pressure, which occurs when cerebrospinal fluid
in the brain exhibits heavy pressure and decreased blood flow, resulting in throbbing headache or nausea for the patient. Astroblastoma is rarely observed in the oncology sphere, accounting for only 0.45% - 2.8% of all brain gliomas since its discovery in 1926. Astroblastoma remains one of the most challenging, problematic tumors to diagnose and treat among the nervous system cancers.
Classification=
The World Health Organization
, a specialized agency that classifies abnormal tumors affecting the central nervous system and assesses potential risk to life, has difficulty in assigning a proper grade for astroblastoma. The organization’s most recent grade in 2007 assigned astroblastoma as a high-grade III and grade IV neoplasm, signifying that the glial tumor is dangerous for patients, causing fatal problems even after surgery. However, recent data compilation from 2011, one that compiled nearly 30 years of clinical information, confirms opposite results from patients: a 95% survival rate exists after astroblastoma is completely removed (gross total resection). The most important factor for any patient when cancer is concerned – the likelihood of surviving – is still controversial for astroblastoma, but recent advances in the last decade have improved prognosis.
Subtypes=
Astroblastoma can be divided into low-grade, well-differentiated tumors and high-grade, anaplastic subtypes. . The majority of tumors exhibit a spherical perimeter with either a solid or cystic interior, comprising peripheral vasculature and epithelioid
neoplasms.
with punctate (pointed) and globular features was noted in a 2009 study of a 12 year-old girl Computerized tomography confirmed these calcified masses in the posteroinferior region to the fourth ventricle
just above the midline. The mass began at the brainstem, extended along the inferior cerebellar peduncle
to roof areas against the ventricles through the nodule of vermis, easily detected against normal grey matter surrounding it. Calcification deriving from nervous system tumors is a rare quality in astroblastoma patients, but it is nonetheless easy to identify. Lumbar pain and lower body weakness is also a rarity in astroblastoma patients, even thought it is entirely possible for lesions to proliferate toward the spinal cord.
, another frequent tumor occurring in the fourth ventricle. In general, when brain lesions are smaller than Grade I, demarcating between these features is near impossible to distinguish, often mistaking astroblastoma with glial neoplasms, high-grade astrocytes, and embryonal neoplasms. However, the “bubbly” appearance in astroblastoma is entirely unique.
Researchers have also confirmed astroblastoma distinct from olidendrogliomas, which are invasive nodular cysts that may resemble a "bubbly" interior. Pleomorphic xanthoastrocytoma, dysembryoplastic neuroepithelial tumor, juvenile pilocytic astrocytomas, and hemangioblastomas are mural nodules with a single cyst appearance that mimics a peripheral vasculature, but further histology has confirmed that a pseudorosette structure as unique in astroblastoma. Advances in the 21st century of histology have justified the proper diagnosis of astroblastoma in the medical community, eliminating confusion that often plagued the tumor in the past.
Research going back to early 2000 marks the first complications for satisfying requirements in radiographic and histopathologic studies. Seven astroblastoma cases of comparative genomic hybridization
, a molecular technique analyzing chromosomal changes in DNA content of brain cancer cells, suggested that chromosome 19 and chromosome 20q were amplified in astroblastoma cells throughout the brain. These genomic features are responsible for widespread proliferation, tumorigenesis, and deregulation of pathways associated with normal housekeeping. Furthermore, the absence of chromosome function in 9q, 10, and X were not observed in other types of neoplasms, such as an ependymoma. Specific neuronal markers further distinguish astroblastoma. Neuron-specific enolase (NSE) positive, NSE negative,synaptophysin
negative, neurofilament negative, TUJ1 positive, and nestin
positive have been expressed in astroblastoma cell populations, which shows significant promise in neuronal stem cell treatment for the tumor.
Clinical Symptoms=
The majority of patients with astroblastoma display a limited set of physical and physiological symptoms. Rare cases in literature reveal atypical conditions, but these are often exclusive to the individual and do not suggest a widespread trend. As research continues, a larger set of symptoms can be properly assessed in the clinic.
Most patients experience a series of intermittent headaches over a few weeks or sustained, powerful pressure in a matter of days. The time-frame for this pressure varies from patient to patient and fluctuate based on the stage of the tumor. Both low-grade and high-grade astroblastoma can exhibit significant discomfort from headaches, although literature supports that higher-grade astroblastoma affect a patient with day-to-day activities, forcing individuals to stay at home away from their jobs and family. Maligant astroblastoma distorts the function of surrounding brain regions, and pressure is the primary result.
Along with cranial pressure, patients exhibit noticeable lethargy, increasing in severity as the tumor progresses. In the first few months, morning activities are usually unaffected; over time, these effects become more pronounced, especially late at night. Lethargy can disrupt vital signs, depleting energy and desire to perform simple cognitive tasks.
The desire to eat normally becomes worse over time, leading to weight loss from vomiting. Nausea is seen in almost all cases of astroblastoma, especially in low-grade tumors.
Vision deficit usually occurs when lesions grow in the occipital lobe of the brain, causing a blurred daze for patients, especially in sensitivity to light. Focusing upon finer objects becomes a challenge, along with edge and border detection. Driving behind the wheel is dangerous when astroblastoma grows in residual tissue size, since peripheral vision can be insufficient. Horizontal nystagmus
and other involuntary eye disorders can occur.
Frequent reports show that adolescents and adults with grade III and IV astroblastoma fall frequently before they even reach a doctor's office. Alertness is diminished when walking normally, forcing patients to exhibit awkward gait patterns to avoid imbalance.
Since the motor system can be impaired with severe cases, the malignant spread of astroblastoma throughout the body may also paralyze the spinal cord, diminish sensation in upper and lower extremities, or sequester gustation.
Grade III and IV astroblastoma have been shown gradually change the mental stability of a patient. Hallucinations impair cognition to the point where patients a lost of identity, although this is not commonly seen in clinic.
Irritability, aggression, memory and neurological deficits, and inattentiveness on everyday tasks are the most common forms of dyregulation in the mental capabilities of a patient. Verbal communication is affected, but usually not to the point where close friends can detect that the individual is cognitively impaired.
Overall, case reports indicate that mild headaches, drowsiness, nausea, and weakness in motor systems are the most observed symptoms in general clinics. Normally, physicians will deem an astroblastoma as simply a "brain mass," referring cases towards certified oncologists. Magnetic resonance imaging
is the preliminary technique for oncologists to evaluate the degree of swelling. Some patients never notice these physical symptoms until the astroblastoma further develops, causing a sudden peak of physical and mental stress If the tumor is undiagnosed for a longer period of time, injuries can occur when the patient least expects an accuident. Additional medical problems may accentuate the more bizarre characteristics of a patient, especially in psychotic changes or personality disorders from the tumor.
Epidemiology=
Astroblastoma mainly affects children and young adults. The tumor is considered a pediatric disease, but older patients are also seen throughout literature.
Most diagnosis occurs from ages 5-10 and ages 15-20 A combination of anatomic location and image assessment can be coupled with age to efficiently evaluate astroblastoma.
In reported cases of the tumor over the last 25 years, the number of affected females with astroblastoma is higher than the number of affected males. Several publications have confirmed that astroblastoma is genetically predisposed to females, but the underlying reasons to this phenomena is still unknown
At this point, no research has indicated whether environmental factors or activities increase the likelihood of astroblastoma. Although cancer in general is caused by a variety of factors, astroblastoma research has not even attempted to classify incidence in this regard.
Recurrence=
More than other brain tumors, astroblastoma is distinct in that its recurrence rate is observed in several case reports that offered resection as treatment. Currently, an unfavorable prognosis exists for patients with high-grade, anaplastic astroblastoma: they tend to recur almost indefinitely, forcing the patient to invest in more invasive surgeries. In contrast, a favorable prognosis exists for patients with well-differentiated, low-grade astroblastoma, since patients usually never require such a treatment The strict black-and-white diagnosis of an astroblastoma based on grade does not determine all tumor behaviors, but it can be used as a benchmark for patients with varying degrees of severity.
The likelihood of low-grade astroblastoma returning after surgery is highly improbable, but some patients have exhibited recurrence. Patients with low-grade lesions can remain asymptomatic after surgery and show recurrence 1-2 years in follow-up sessions. However, since residual tissue size is a large determinant for profiling recurrence, it is almost never the case that a low-grade astroblastoma continues to appear in size and strength after the second resection. Usually, patients are not recommended for resection at all and are simply directed towards other therapeutic techniques. Most children can continue to lead productive, healthy lives after a low-grade astroblastoma is treated.
Surviving the symptoms of high-grade astroblastoma is not life-threatening, but a significant portion of patients die due the repeated recurrence of tumors as they continue to grow. Unlike conventional low-grade tumors, high-grade tumors associate a plethora of factors when they metastasize to other areas of the body. Therefore, complications frequently occur after surgery is performed since an oncologist cannot efficiently control the tumor in a suitable time-frame. "Unal"/> Cases in literature confirm that high-grade patients face up to five or six resection surgeries and still experience symptoms post-operatively. The dual-action of chemotherapy and radiotherapy can slow down recurrence when gross total resection is performed multiple times.
Treatment=
Like most tumors in the brain, astroblastoma can be treated through surgery and various forms of therapy. Remission from the tumor is not a guarantee, but many publications within the last decade have suggested a noticeable improvement in success rate of patients. With the advancement of cutting-edge technology and novel approaches in stem cells, patients are hopeful that they be happy and healthy through old age.
Complete surgical resection, known as gross-total resection, remains the standard for treating astroblastoma, despite high recurrence rate for high-grade tumors. Since there are so few cases reported around the world each year, the standard for surgery varies from physician to physician and is often difficult to rightfully diagnose. Low-grade astroblastomas exhibit low recurrence rates following resection, but varying reports prove that some patients, despite the severity of the lesion, will unpredictably witness recurrence. In a recent study of a 17-year-old male, a low-grade astroblastoma was resected and recurred within 5 months of the therapy, forcing the oncologist to administer further chemotherapy, radiotherapy, and a second resection to completely put the tumor in remission.
The use of radiation therapy after an astroblastoma excision has variable results. Conventional external beam radiation has both positive and negative effects on patients, but it is not recommended at this point to treat all types. All in all, the radiosensitivity of astroblastoma to therapy remains unclear, since some research advocate its effectiveness while others diminish the effects. Future studies must be done on patients with both total excision and sub-excision of the tumor to accurately assess whether radiation benefits patients under different circumstances.
Normally, chemotherapy is not recommended until the second required resection, which implies that the astroblastoma is a high-grade tumor continuing to recur every few months. A standard chemotherapy protocol starts with two rounds of nimustine hydrochoride (ACNU), etoposide
, vincristine
, and interferon-beta.. The patient undergoes am strict drug regimen until another surgery is required. By the third surgery, should recurrence in the astroblastoma occur, a six-round program ifosfamide
,cisplatin
, and etoposide
will "shock" the patient's system to the point where recurrence is halted. Unfortunately, chemotherapy may not always be successful with patients requiring further resection of the tumor, since the tumor cell begins to show superior vasculature and a strong likelihood of compromising a patient's well-being. Oral ingestion of temozolomide
for at-home bedside use may be preferred by the patient.
A popular and new-age form of surgery involves Cyberknife
radiotherapy and Gamma Knife radiosurgery. Their success-rate on cranial lesion is fairly effective, but recurrence is still a problem for severe patients.
One of the more exciting and promising routes for treatment involves stem cell use to combat astroblastoma. A study in 2005 profiled cell surface markers of astroblastoma cells removed from a 11 year-old patient. Fluorescence activation suggested that about 1/4 of these cells from were CD133
positive and CD24
, CD34
, and CD45
negative, a specific genetic makeup that lends to self-renewal, differentiation, and propagation of neural stem cells in the brain. However, the work remains a preliminary insight into the role of neuronal stemlike cells on astroblastoma development.
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
derived from the astroblast, a type of cell that closely resembles spongioblastoma and astrocytes. Astroblastoma cells are most likely found in the supratentorial region of the brain that houses the cerebrum, an area responsible for all voluntary movements in the body. It also occurs significantly in the frontal, parietal, and temporal regions, areas where movement, language creation, memory perception, and environmental surroundings are expressed. These tumors can be present in major brain areas not associated with the main cerebral hemispheres, including the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
, optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
, cauda equina
Cauda equina
The cauda equina is a structure within the lower end of the spinal column of most vertebrates, that consists of nerve roots and rootlets from above...
, hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
, and brain stem
Brain stem
In vertebrate anatomy the brainstem is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves...
.
The most defining symptom of astroblastoma, regardless of location, is elevated intracranial pressure, which occurs when cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
in the brain exhibits heavy pressure and decreased blood flow, resulting in throbbing headache or nausea for the patient. Astroblastoma is rarely observed in the oncology sphere, accounting for only 0.45% - 2.8% of all brain gliomas since its discovery in 1926. Astroblastoma remains one of the most challenging, problematic tumors to diagnose and treat among the nervous system cancers.
Classification=
The World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
, a specialized agency that classifies abnormal tumors affecting the central nervous system and assesses potential risk to life, has difficulty in assigning a proper grade for astroblastoma. The organization’s most recent grade in 2007 assigned astroblastoma as a high-grade III and grade IV neoplasm, signifying that the glial tumor is dangerous for patients, causing fatal problems even after surgery. However, recent data compilation from 2011, one that compiled nearly 30 years of clinical information, confirms opposite results from patients: a 95% survival rate exists after astroblastoma is completely removed (gross total resection). The most important factor for any patient when cancer is concerned – the likelihood of surviving – is still controversial for astroblastoma, but recent advances in the last decade have improved prognosis.
Subtypes=
Astroblastoma can be divided into low-grade, well-differentiated tumors and high-grade, anaplastic subtypes. . The majority of tumors exhibit a spherical perimeter with either a solid or cystic interior, comprising peripheral vasculature and epithelioid
Epithelioid
An epithelioid cell is a cell that resembles epithelial cells in that it directly contacts its neighboring cells via cell surface molecules or junctions. Unlike epithelial cells, however, epithelioid cells make contacts over their entire surface, rather than at restricted portions. The term...
neoplasms.
General Pathology
Since the early 1990's, astroblastoma has established a stable set of pathological qualities that truly distinguishes itself as a separate and significant entity. Compilations from various case reports reveal the following common characteristics:- Appears "bubbly" in nature
- Polarized, unipolar in structure
- Peripheral vasculature
- Radial arrangement as a pseudorosette
- Immunoreactive for GFAP and vimentinVimentinVimentin is a type III intermediate filament protein that is expressed in mesenchymal cells. IF proteins are found in all metazoan cells as well as bacteria. IF, along with tubulin-based microtubules and actin-based microfilaments, comprise the cytoskeleton...
(supports astrocytic origin) - Lacks "true rosetteRosette-People:* Rosette , a French actress* Rosette Bir , a French sculptor* Clinton Rosette , a prominent citizen of DeKalb, Illinois...
" architecture - Lacks structural cohesiveness
- Prominent pseudopapillae formation
- Localization mostly in cerebral hemispheres
- Nodular, non-invasive growth
- Strong, associative vasculature in other parts of the body
- Vascular fibrosis prominence
- High likelihood of hyalinization
- Low likelhood to metastasize toward other regions of the brain
Abnormal Pathology
Beyond normal pathologies, scientists have confirmed some abnormal characteristics of astroblastoma in a variety of patients. The presence of a bulky calcificationCalcification
Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...
with punctate (pointed) and globular features was noted in a 2009 study of a 12 year-old girl Computerized tomography confirmed these calcified masses in the posteroinferior region to the fourth ventricle
Fourth ventricle
The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle...
just above the midline. The mass began at the brainstem, extended along the inferior cerebellar peduncle
Inferior cerebellar peduncle
The upper part of the posterior district of the medulla oblongata is occupied by the inferior cerebellar peduncle , a thick rope-like strand situated between the lower part of the fourth ventricle and the roots of the glossopharyngeal and vagus nerves.Each cerebellar inferior peduncle connects the...
to roof areas against the ventricles through the nodule of vermis, easily detected against normal grey matter surrounding it. Calcification deriving from nervous system tumors is a rare quality in astroblastoma patients, but it is nonetheless easy to identify. Lumbar pain and lower body weakness is also a rarity in astroblastoma patients, even thought it is entirely possible for lesions to proliferate toward the spinal cord.
Associations with Other Tumors
An enormous difficulty lies in classifying an astroblastoma tumor due to its overlapping features with other brain tumors. Certain neuroradiologic features finally distinguish astroblastoma from the common ependymomaEpendymoma
Ependymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in pediatric cases the location is intracranial, while in adults it is spinal. The common location of intracranial ependymoma is the fourth ventricle...
, another frequent tumor occurring in the fourth ventricle. In general, when brain lesions are smaller than Grade I, demarcating between these features is near impossible to distinguish, often mistaking astroblastoma with glial neoplasms, high-grade astrocytes, and embryonal neoplasms. However, the “bubbly” appearance in astroblastoma is entirely unique.
Researchers have also confirmed astroblastoma distinct from olidendrogliomas, which are invasive nodular cysts that may resemble a "bubbly" interior. Pleomorphic xanthoastrocytoma, dysembryoplastic neuroepithelial tumor, juvenile pilocytic astrocytomas, and hemangioblastomas are mural nodules with a single cyst appearance that mimics a peripheral vasculature, but further histology has confirmed that a pseudorosette structure as unique in astroblastoma. Advances in the 21st century of histology have justified the proper diagnosis of astroblastoma in the medical community, eliminating confusion that often plagued the tumor in the past.
Research going back to early 2000 marks the first complications for satisfying requirements in radiographic and histopathologic studies. Seven astroblastoma cases of comparative genomic hybridization
Comparative genomic hybridization
Comparative genomic hybridization or Chromosomal Microarray Analysis is a molecular-cytogenetic method for the analysis of copy number changes in the DNA content of a given subject's DNA and often in tumor cells....
, a molecular technique analyzing chromosomal changes in DNA content of brain cancer cells, suggested that chromosome 19 and chromosome 20q were amplified in astroblastoma cells throughout the brain. These genomic features are responsible for widespread proliferation, tumorigenesis, and deregulation of pathways associated with normal housekeeping. Furthermore, the absence of chromosome function in 9q, 10, and X were not observed in other types of neoplasms, such as an ependymoma. Specific neuronal markers further distinguish astroblastoma. Neuron-specific enolase (NSE) positive, NSE negative,synaptophysin
Synaptophysin
Synaptophysin also known as the major synaptic vesicle protein p38 is a protein that in humans is encoded by the SYP gene.-Genomics:...
negative, neurofilament negative, TUJ1 positive, and nestin
Nestin
Nestin may refer to:* Neštin, a village in Srem, Vojvodina, Serbia.* Nestin , a type VI intermediate filament protein....
positive have been expressed in astroblastoma cell populations, which shows significant promise in neuronal stem cell treatment for the tumor.
Clinical Symptoms=
The majority of patients with astroblastoma display a limited set of physical and physiological symptoms. Rare cases in literature reveal atypical conditions, but these are often exclusive to the individual and do not suggest a widespread trend. As research continues, a larger set of symptoms can be properly assessed in the clinic.
Intracranial pressure
Most patients experience a series of intermittent headaches over a few weeks or sustained, powerful pressure in a matter of days. The time-frame for this pressure varies from patient to patient and fluctuate based on the stage of the tumor. Both low-grade and high-grade astroblastoma can exhibit significant discomfort from headaches, although literature supports that higher-grade astroblastoma affect a patient with day-to-day activities, forcing individuals to stay at home away from their jobs and family. Maligant astroblastoma distorts the function of surrounding brain regions, and pressure is the primary result.
Enhanced drowsiness
Along with cranial pressure, patients exhibit noticeable lethargy, increasing in severity as the tumor progresses. In the first few months, morning activities are usually unaffected; over time, these effects become more pronounced, especially late at night. Lethargy can disrupt vital signs, depleting energy and desire to perform simple cognitive tasks.
Frequent nausea
The desire to eat normally becomes worse over time, leading to weight loss from vomiting. Nausea is seen in almost all cases of astroblastoma, especially in low-grade tumors.
Impaired vision
Vision deficit usually occurs when lesions grow in the occipital lobe of the brain, causing a blurred daze for patients, especially in sensitivity to light. Focusing upon finer objects becomes a challenge, along with edge and border detection. Driving behind the wheel is dangerous when astroblastoma grows in residual tissue size, since peripheral vision can be insufficient. Horizontal nystagmus
Nystagmus
Nystagmus is a condition of involuntary eye movement, acquired in infancy or later in life, that may result in reduced or limited vision.There are two key forms of Nystagmus: pathological and physiological, with variations within each type. Nystagmus may be caused by congenital disorders,...
and other involuntary eye disorders can occur.
Motor system imbalance and weakness
Frequent reports show that adolescents and adults with grade III and IV astroblastoma fall frequently before they even reach a doctor's office. Alertness is diminished when walking normally, forcing patients to exhibit awkward gait patterns to avoid imbalance.
Decreased sensation
Since the motor system can be impaired with severe cases, the malignant spread of astroblastoma throughout the body may also paralyze the spinal cord, diminish sensation in upper and lower extremities, or sequester gustation.
Psychotic episodes
Grade III and IV astroblastoma have been shown gradually change the mental stability of a patient. Hallucinations impair cognition to the point where patients a lost of identity, although this is not commonly seen in clinic.
Cognitive dysregulation
Irritability, aggression, memory and neurological deficits, and inattentiveness on everyday tasks are the most common forms of dyregulation in the mental capabilities of a patient. Verbal communication is affected, but usually not to the point where close friends can detect that the individual is cognitively impaired.
Overall, case reports indicate that mild headaches, drowsiness, nausea, and weakness in motor systems are the most observed symptoms in general clinics. Normally, physicians will deem an astroblastoma as simply a "brain mass," referring cases towards certified oncologists. Magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
is the preliminary technique for oncologists to evaluate the degree of swelling. Some patients never notice these physical symptoms until the astroblastoma further develops, causing a sudden peak of physical and mental stress If the tumor is undiagnosed for a longer period of time, injuries can occur when the patient least expects an accuident. Additional medical problems may accentuate the more bizarre characteristics of a patient, especially in psychotic changes or personality disorders from the tumor.
Epidemiology=
Astroblastoma mainly affects children and young adults. The tumor is considered a pediatric disease, but older patients are also seen throughout literature.
Age Incidence
Most diagnosis occurs from ages 5-10 and ages 15-20 A combination of anatomic location and image assessment can be coupled with age to efficiently evaluate astroblastoma.
Gender Incidence
In reported cases of the tumor over the last 25 years, the number of affected females with astroblastoma is higher than the number of affected males. Several publications have confirmed that astroblastoma is genetically predisposed to females, but the underlying reasons to this phenomena is still unknown
Environmental Incidence
At this point, no research has indicated whether environmental factors or activities increase the likelihood of astroblastoma. Although cancer in general is caused by a variety of factors, astroblastoma research has not even attempted to classify incidence in this regard.
Recurrence=
More than other brain tumors, astroblastoma is distinct in that its recurrence rate is observed in several case reports that offered resection as treatment. Currently, an unfavorable prognosis exists for patients with high-grade, anaplastic astroblastoma: they tend to recur almost indefinitely, forcing the patient to invest in more invasive surgeries. In contrast, a favorable prognosis exists for patients with well-differentiated, low-grade astroblastoma, since patients usually never require such a treatment The strict black-and-white diagnosis of an astroblastoma based on grade does not determine all tumor behaviors, but it can be used as a benchmark for patients with varying degrees of severity.
Low-grade
The likelihood of low-grade astroblastoma returning after surgery is highly improbable, but some patients have exhibited recurrence. Patients with low-grade lesions can remain asymptomatic after surgery and show recurrence 1-2 years in follow-up sessions. However, since residual tissue size is a large determinant for profiling recurrence, it is almost never the case that a low-grade astroblastoma continues to appear in size and strength after the second resection. Usually, patients are not recommended for resection at all and are simply directed towards other therapeutic techniques. Most children can continue to lead productive, healthy lives after a low-grade astroblastoma is treated.
High-grade
Surviving the symptoms of high-grade astroblastoma is not life-threatening, but a significant portion of patients die due the repeated recurrence of tumors as they continue to grow. Unlike conventional low-grade tumors, high-grade tumors associate a plethora of factors when they metastasize to other areas of the body. Therefore, complications frequently occur after surgery is performed since an oncologist cannot efficiently control the tumor in a suitable time-frame. "Unal"/> Cases in literature confirm that high-grade patients face up to five or six resection surgeries and still experience symptoms post-operatively. The dual-action of chemotherapy and radiotherapy can slow down recurrence when gross total resection is performed multiple times.
Treatment=
Like most tumors in the brain, astroblastoma can be treated through surgery and various forms of therapy. Remission from the tumor is not a guarantee, but many publications within the last decade have suggested a noticeable improvement in success rate of patients. With the advancement of cutting-edge technology and novel approaches in stem cells, patients are hopeful that they be happy and healthy through old age.
Gross-total resection
Complete surgical resection, known as gross-total resection, remains the standard for treating astroblastoma, despite high recurrence rate for high-grade tumors. Since there are so few cases reported around the world each year, the standard for surgery varies from physician to physician and is often difficult to rightfully diagnose. Low-grade astroblastomas exhibit low recurrence rates following resection, but varying reports prove that some patients, despite the severity of the lesion, will unpredictably witness recurrence. In a recent study of a 17-year-old male, a low-grade astroblastoma was resected and recurred within 5 months of the therapy, forcing the oncologist to administer further chemotherapy, radiotherapy, and a second resection to completely put the tumor in remission.
Radiotherapy
The use of radiation therapy after an astroblastoma excision has variable results. Conventional external beam radiation has both positive and negative effects on patients, but it is not recommended at this point to treat all types. All in all, the radiosensitivity of astroblastoma to therapy remains unclear, since some research advocate its effectiveness while others diminish the effects. Future studies must be done on patients with both total excision and sub-excision of the tumor to accurately assess whether radiation benefits patients under different circumstances.
Chemotherapy
Normally, chemotherapy is not recommended until the second required resection, which implies that the astroblastoma is a high-grade tumor continuing to recur every few months. A standard chemotherapy protocol starts with two rounds of nimustine hydrochoride (ACNU), etoposide
Etoposide
Etoposide phosphate is an anti-cancer agent. It is known in the laboratory as a topoisomerase poison. Etoposide is often incorrectly referred to as a topoisomerase inhibitor in order to avoid using the term "poison" in a clinical setting...
, vincristine
Vincristine
Vincristine , formally known as leurocristine, sometimes abbreviated "VCR", is a vinca alkaloid from the Catharanthus roseus , formerly Vinca rosea and hence its name. It is a mitotic inhibitor, and is used in cancer chemotherapy.-Mechanism:Tubulin is a structural protein that polymerizes to...
, and interferon-beta.. The patient undergoes am strict drug regimen until another surgery is required. By the third surgery, should recurrence in the astroblastoma occur, a six-round program ifosfamide
Ifosfamide
Ifosfamide is a nitrogen mustard alkylating agent used in the treatment of cancer.It is sometimes abbreviated "IFO".-Uses:It is given as a treatment for a variety of cancers, including:...
,cisplatin
Cisplatin
Cisplatin, cisplatinum, or cis-diamminedichloroplatinum is a chemotherapy drug. It is used to treat various types of cancers, including sarcomas, some carcinomas , lymphomas, and germ cell tumors...
, and etoposide
Etoposide
Etoposide phosphate is an anti-cancer agent. It is known in the laboratory as a topoisomerase poison. Etoposide is often incorrectly referred to as a topoisomerase inhibitor in order to avoid using the term "poison" in a clinical setting...
will "shock" the patient's system to the point where recurrence is halted. Unfortunately, chemotherapy may not always be successful with patients requiring further resection of the tumor, since the tumor cell begins to show superior vasculature and a strong likelihood of compromising a patient's well-being. Oral ingestion of temozolomide
Temozolomide
Temozolomide Temozolomide Temozolomide (brand names Temodar and Temodal is an oral alkylating agent which can be used for the treatment of Grade IV astrocytoma — an aggressive brain tumor, also known as glioblastoma multiforme as well as melanoma, a form of skin cancer...
for at-home bedside use may be preferred by the patient.
Future Considerations
A popular and new-age form of surgery involves Cyberknife
Cyberknife
The CyberKnife is a frameless robotic radiosurgery system used for treating benign tumors, malignant tumors and other medical conditions. The system was invented by John R. Adler, a Stanford University Professor of Neurosurgery and Radiation Oncology, and Peter and Russell Schonberg of Schonberg...
radiotherapy and Gamma Knife radiosurgery. Their success-rate on cranial lesion is fairly effective, but recurrence is still a problem for severe patients.
One of the more exciting and promising routes for treatment involves stem cell use to combat astroblastoma. A study in 2005 profiled cell surface markers of astroblastoma cells removed from a 11 year-old patient. Fluorescence activation suggested that about 1/4 of these cells from were CD133
CD133
CD133, originally known as AC133. CD133 is a glycoprotein also known in humans and rodents as Prominin 1 . Currently the function of CD133 is unknown...
positive and CD24
CD24
Signal transducer CD24 also known as cluster of differentiation 24 or heat stable antigen CD24 is a protein that in humans is encoded by the CD24 gene. CD24 is a cell adhesion molecule.- Function :...
, CD34
CD34
CD34 molecule is a cluster of differentiation molecule present on certain cells within the human body. It is a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells...
, and CD45
CD45
Protein tyrosine phosphatase, receptor type, C also known as PTPRC is an enzyme that, in humans, is encoded by the PTPRC gene. PTPRC is also known as CD45 antigen , which was originally called leukocyte common antigen.- Function :The protein encoded by this gene is a member of the protein tyrosine...
negative, a specific genetic makeup that lends to self-renewal, differentiation, and propagation of neural stem cells in the brain. However, the work remains a preliminary insight into the role of neuronal stemlike cells on astroblastoma development.