|Year : 2015 | Volume
| Issue : 3 | Page : 667
Astroblastoma of cerebrum: A rare case report and review of literature
Satya Narayan1, Akhil Kapoor1, Mukesh Kumar Singhal1, Shankar Lal Jakhar1, Puneet Kumar Bagri1, Prakash Singh Rajput2, Harvindra Singh Kumar1
1 Department of Radiation Oncology, Acharya Tulsi Regional Cancer Treatment and Research Institute, Bikaner, Rajasthan, India
2 Department of Pathology, Sardar Patel Medical College, Bikaner, Rajasthan, India
|Date of Web Publication||9-Oct-2015|
Department of Radiation Oncology, Acharya Tulsi Regional Cancer Treatment and Research Institute, Bikaner, Rajasthan
Source of Support: None, Conflict of Interest: None
Astroblastoma is a rare neuroepithelial primary brain tumor of uncertain origin. They form 0.45-2.8% of all the neuroglial tumors. This tumor is usually localized in the cerebral hemisphere of young adults and children. The authors report a case of low-grade astroblastoma in a 16-year-old male and review the relevant literature. The patient presented with 2 months history of progressive headache with projectile vomiting for last 2 months. He underwent gross total resection of the lesion through right temporo-occipital craniotomy. Since tumor showed no evidence of high-grade lesion, adjuvant radiotherapy was not planned. However, the patient developed recurrence of the tumor after 12 months. Localized three-dimensional conformal radiotherapy was planned. In patients harboring anaplastic astroblastoma, gross-total resection and adjuvant therapy after the initial surgery seems to be the best choice. They can be easily misdiagnosed as they are rarely encountered in clinical practice and share common radiological and histopathologic appearance with other glial neoplasms.
Keywords: Adjuvant radiotherapy, astroblastoma, case report, cerebral, recurrence
|How to cite this article:|
Narayan S, Kapoor A, Singhal MK, Jakhar SL, Bagri PK, Rajput PS, Kumar HS. Astroblastoma of cerebrum: A rare case report and review of literature. J Can Res Ther 2015;11:667
|How to cite this URL:|
Narayan S, Kapoor A, Singhal MK, Jakhar SL, Bagri PK, Rajput PS, Kumar HS. Astroblastoma of cerebrum: A rare case report and review of literature. J Can Res Ther [serial online] 2015 [cited 2020 Aug 10];11:667. Available from: http://www.cancerjournal.net/text.asp?2015/11/3/667/140800
| > Introduction|| |
Astroblastomas are rare neuroepithelial primary brain tumors of uncertain origin. They form 0.45-2.8% of all the neuroglial tumors.  This tumor is usually located in the cerebral hemisphere of young adults and children.  Only histopathology may be insufficient to provide a clear diagnosis in these rare tumors and thus, immunohistochemistry, molecular biology, and neuro-imaging come into play. Further, ependymomas share histological features with astroblastoma and must be differentiated carefully.  The authors report a case of low-grade astroblastoma in a 16-year-old male and review the relevant literature.
| > Case report|| |
A 16-year-old, otherwise healthy boy presented with progressive headache and projectile vomiting for 2 months. The neurological examination showed right sixth nerve paresis with bilateral papilledema. Magnetic resonance imaging (MRI) revealed a heterogeneous mass lesion with cystic and solid components with perilesional edema in right temporo-occipital lobe with mid-line shift and transtentorial herniation. It was hypointense on T1-weighted [Figure 1]a and heterogeneously hyperintense on T2-weighted images with peripheral punctuate calcifications [Figure 1]b. The above images were reported as intermediate grade glioma. The patient underwent gross-total resection of the lesion through right temporo-occipital craniotomy [Figure 1]c. Postoperative period was uneventful and neurological examination did not reveal any additional deficits. Microscopically, tumor showed perivascular pseudorosette present diffusely throughout the lesion with vascular hyalinization [Figure 2]. Separate papillary projections were also seen having individual radiating thick, short and blunt cytoplasmic processes around the blood vessels. There was absence of any features of necrosis with lack of fibrillary background. Focal nuclear pleomorphism was present. Tumor showed little infiltration of the surrounding normal brain. The histopathologic diagnosis was low-grade astroblastoma. Immunohistochemistry revealed glial fibrillary acidic protein (GFAP), vimentin, and S-100 positivity. Synaptophysin was very focally positive. Epithelial membrane antigen and pan-cytokeratin were negative. p53 was approximately <10%. Ki-67 proliferation index was approximately 2-4%. There was absence of H3F3A and isocitrate dehydrogenase mutations. Postoperative computed tomography (CT) scan showed no residual lesion [Figure 1]c. Since tumor showed no evidence of high-grade lesion, adjuvant radiotherapy was not planned. A scan at 2 months follow-up showed no evidence of mitotic lesion. The patient remained free of symptoms for 12 months after neurosurgery and then developed progressive headache. CT scan revealed recurrent lesion in right posterior temporal lobe [Figure 3]a and b. The biopsy of the recurrent lesion confirmed the histologic features of recurrent astoblastoma. Cerebrospinal fluid examination was negative for malignant cells. Thus, localized three-dimensional conformal radiotherapy was planned.
|Figure 1: (a) T1-weighted magnetic resonance image showing hypointense heterogeneous mass lesion with perilesional edema in right temporo-occipital lobe. (b) T2-weighted magnetic resonance image showing hyperintense mass lesion. (c) Postoperative computed tomography scan showing complete excision of the tumor|
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|Figure 2: Microscopic view (×40) showing (a) perivascular pseudorosette, (b) hyalinization|
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|Figure 3: Computed tomography scan after 1 year suggestive of recurrence of the tumor|
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| > Discussion|| |
Astroblastoma have been reported sporadically in the literature since Bailey and Bucy reported the condition for the first time in 1930.  Astroblastoma is a rare tumor that occurs in cerebral hemisphere (significantly in the frontal lobe, parietal lobe, and temporal lobe). Other rare sites include cerebellum, optic nerve, cauda equina, hypothalamus, and brain stem.  The cell of origin of astroblastoma is still a debatable entity as they share features of both astrocytoma and ependymoma, but now the cell of origin is widely accepted to be the astroblast as an intermediate cell between spongioblast and astrocytes. Recent histologic and comparative genomic findings have suggested that astroblastoma is indeed a distinct entity.  Brain tanycytes are now thought to give rise to these tumors. Tanycytes were first described by Horstmann in 1954.  They are a variety of ependymal cells present in the floor of the fourth ventricle of the brain. Their processes end on vessels and neurons. A lot of evidence suggests that tanycytes are involved in neuropeptide transport. Tanycytes have ultrastructural resemblance with some rare brain tumors like subependymoma and astroblastoma. These tumors are now sometimes referred to as tanycytomas.  Clinically, raised intracranial pressure and seizure episodes remain the common presentation. Other may present with signs and symptoms pertaining to anatomical structures involved such as visual loss, memory disturbances, seizures, weakness, and altered sensorium. 
On MRI, these tumors tend to be large lobulated masses, which characteristically extend from the peripheral cortex to the periventricular region. T1- and T2-weighted sequences of these tumors appear well-demarcated, heterogeneous solid-cystic components with inhomogeneous contrast enhancement. Solid component gives typical heterogeneous appearance on MRI, and peritumoral T2 hyperintensity is less compared to large their size.  In spite of the characteristic imaging features, they are usually confused for glioma, primitive neuroectodermal tumors, or ependymoma. ,[ 6]
Histologically these tumors are characterized by perivascular pseudorosette throughout the tumor tissue more distinctly observed in solid areas of tumor.  Most of the tumor cells are monotonous with coarse chromatin arrangement pattern. These rosettes are characterized by short and thick blunt ended foot plates of astroblastoma cells directed toward the central blood vessel. These pseudorosette are also observed in glioblastoma and anaplastic astrocytoma, but appearance remains focal, while in astroblastoma these are spread all over the tumor tissue. Ependymoma also can have pseudorosette, but arrangement of cells remains more compact and cytoplasmic processes are thin, tapering toward central vessel and often fibrillated compared to thick and blunt ended in astroblastoma cells.  Blood vessels in tumor tissue show areas of hyalinization. Some nonneural tumors also show the presence of pseudorosette, but they can be excluded on immunohistochemical demonstration of GFAP. , In the case of the equivocal histological findings, MRI may play a crucial role in establishing a diagnosis.
Surgical excision of the tumor remains the mainstay of the treatment, which achieves decompression of tumor relieving raised intracranial pressure and decreases the cellular load. As these tumors generally present with raised intracranial pressure, role of surgery as a primary therapy is well-justified. ,,[ 12] In postoperative period, chemotherapy and radiotherapy have been tried in different series with limited success.  The overall prognosis of this tumor remains average with average survival being 4 years after the diagnosis in several series. ,,[ 14] In some patients, chemotherapy with methotrexate, vincristine, and leucovorin have been tried successfully.  The present consensus is to do surgical excision of the patients with postoperative radiotherapy and chemotherapy with the grade of excision being the major determinant of prognosis. 
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[Figure 1], [Figure 2], [Figure 3]