Cerebellar astrocytoma (CA) is a benign tumor of astrocytes or a specific type of glial cell tumor which has been mainly observed in the posterior fossa region (25%) of the brain. Overall, CA accounts for almost 10% of all primary brain tumors. Glial cells are supportive cells to neurons in the brain consisting of astrocytes, oligodendrocytes, ependymal cells, as well as microglia. CA is most evident among children and young adults with well-circumscribed regions, as it is also called juvenile pilocytic astrocytoma. The cerebellum is the vital part of the brain which is responsible for balance and coordinated movements. Pilocytic astrocytoma is synonymously used for cerebellar astrocytoma as it most commonly occurs in the cerebellum.
The majority of CA arises from the central nervous system (CNS). The nature of the tumor is a low grade with patients having long-term survival. CA may lead to increased head circumference with cerebellar lesion-oriented major symptomatic manifestations such as peripheral ataxia, intention tremor, dysmetria, nystagmus, and dysarthria.
Global perspective
According to the WHO, such rare tumors are considered Grade I astrocytomas with a good prognosis. Generally, CA is a pediatric tumor that is caused by ionizing radiations and/or mutations of the BRAF proto-oncogene sporadically. Most pilocytic astrocytomas (90%) are having a global survival mean of 10 years. These Grade I tumors contribute to approximately 5.1 % of all gliomas with males being slightly more affected in comparison to females. Most juvenile pilocytic astrocytomas manifest by the early two decades of life with an estimated incidence rate of 14 new cases per million in children (<15 years).
Indian perspective
According to a study decades ago, emphasis on the role of radiotherapy following surgical resection as the mainstay of pilocytic astrocytoma management was established in India. There is a concern for prognosis which needs to be addressed for the infiltrating types of diffused astrocytomas. However, a recent Indian population study with adult low-grade gliomas has associated p53 mutations and altered microvascular density count to detect early recurrence of aggressive infiltrating diffuse tumor behavior of pilocytic astrocytomas, indicating the malignancies can occur at a higher rate in adults.
Signs and symptoms
Some very common signs are headaches, nausea, vomiting, balance problems along with vision defects. CA can merely be managed through surgical removal with fewer chances of leading to malignancy.
Diagnosis
A diagnosis of CA relies on clinical evaluation and a number of tumor-specific investigations including imaging modalities. Such major imaging techniques are:
Computerized tomography (CT) scans
Magnetic resonance imaging (MRI)
Other than imaging techniques, surgical removal and microscopic evaluation of biopsy samples are done for histopathological confirmation of the diagnosis. A biopsy is not to be sought if the tumor is in the optical axis.
Management
The mainstay of management is surgery, preferably complete resection with minimal neurological damage which can be curative. Post-operative radiotherapy after surgery is required, following time to time monitoring with different imaging techniques for ensuring patients’ quality of life. In case of unfortunate recurrence, further surgical resection may be required. Radiotherapy is the