Childhood Astrocytomas Treatment (PDQ®)–Health Professional Version
General Information About Childhood Astrocytomas
Primary brain tumors, including astrocytomas, are a diverse group of diseases that together constitute the most common solid tumors of childhood. Brain tumors are classified according to histology and molecular features, but tumor location and extent of spread are also important factors that affect treatment and prognosis. Immunohistochemical analysis, cytogenetic and molecular genetic findings, and measures of mitotic activity are used in tumor diagnosis and classification.
Gliomas are thought to arise from glial precursor cells that are present in the brain and spinal cord. Gliomas are named according to their presumed clinicopathologic and histologic subtype. Astrocytoma is the most commonly diagnosed type of glioma in children.
According to the World Health Organization (WHO) classification of brain tumors, gliomas are classified further as low-grade (grades I and II) or high-grade (grades III and IV) tumors. Children with low-grade tumors have a relatively favorable prognosis, especially when the tumors can be completely resected. Children with high-grade tumors generally have a less favorable prognosis, but this is somewhat dependent on subtype.
The PDQ childhood brain tumor treatment summaries are organized primarily according to the WHO classification of nervous system tumors.[1,2] For a full description of the classification of nervous system tumors and a link to the corresponding treatment summary for each type of brain tumor, refer to the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview.
Anatomy
Childhood astrocytomas can occur anywhere in the central nervous system (CNS) (refer to the Figure). Refer to Table 3 for the most common CNS location for each tumor type.
Clinical Features
Presenting symptoms for childhood astrocytomas depend on the following:
- CNS location.
- Size of the tumor.
- Rate of tumor growth.
- Chronologic and developmental age of the child.
In infants and young children, low-grade astrocytomas presenting in the hypothalamus may result in diencephalic syndrome, which is manifested by failure to thrive in an emaciated, seemingly euphoric child. Such children may have little in the way of other neurologic findings, but can have macrocephaly, intermittent lethargy, and visual impairment.[3]
Diagnostic Evaluation
The diagnostic evaluation for astrocytoma includes magnetic resonance imaging (MRI) of the brain or spine. For brain primary tumors, spinal MRI is usually performed in conjunction with the initial brain MRI to exclude neuraxis metastases.
Lumbar punctures examining the cerebrospinal fluid for circulating tumor cells are not commonly performed in children with this disease.
Clinicopathologic Classification of Childhood Astrocytomas and Other Tumors of Glial Origin
The pathologic classification of pediatric brain tumors is a specialized area that is evolving. Examination of the diagnostic tissue by a neuropathologist who has particular expertise in this area is strongly recommended.
Tumor types are based on the putative glial cell type of origin, as follows:
- Astrocytomas (astrocytes).
- Oligodendroglial tumors (oligodendrocytes).
- Mixed gliomas (cell types of origin include oligodendrocytes, astrocytes, and ependymal cells).
- Mixed neuronal-glial tumors.
WHO histologic grade for astrocytic tumors
According to the WHO histologic typing of CNS tumors, childhood astrocytomas and other tumors of glial origin are classified according to clinicopathologic and histologic subtype and are graded (grade I to IV).[1]
WHO histologic grades are commonly referred to as low-grade gliomas or high-grade gliomas (refer to Table 1).
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