Pilocytic astrocytoma

Classification according to ICD-10
D33.0	Benign neoplasm: brain, supratentorial
D33.1	Benign neoplasm: brain, infratentorial (IV ventricle)
ICD-10 online (WHO version 2019)

Magnetic resonance imaging of a pilocytic astrocytoma of the posterior fossa with cystic growth and contrast medium uptake in the area of ​​the brain stem.

The pilocytic astrocytoma is a slow-growing astrocytic brain tumor that occurs mainly in children and young adults and the second most common benign tumor in this age group represents (the most common malignant orbital tumor in childhood rhabdomyosarcoma). As a fine-tissue benign tumor, it is classified as grade I according to the WHO classification of tumors of the central nervous system .

Pilocytic astrocytomas may range from cerebrum , midbrain , the posterior fossa , the spinal cord and also in the course of the optic nerve (optic nerve) and visual pathway (optic tract) may occur, in which latter localization also of Optikusgliomen is spoken. Bilateral optic gliomas are characteristic of neurofibromatosis type 1 .

Clinical manifestation

Frequent disorders are at location of the tumor in the posterior fossa of cerebellar function as unsteady gait ( ataxia ) in the foreground, tumors in the area of the midbrain do inter alia with hypothalamic noticeable malfunction. If the optic nerve or the visual pathway are affected, visual disturbances up to blindness can occur.

morphology

Histology of pilocytic astrocytoma with bundles of bipolar astrocytic tumor cells, Rosenthal fibers, and eosinophilic granular bodies. Hematoxylin-eosin stain . Magnification 200x

Rosenthal fibers in a pilocytic astrocytoma. Hematoxylin-eosin stain . 400x magnification

Macroscopically, these are bulbous, coarse tumors with a gray-white cut surface, often with cystic parts. In terms of tissue, these are astrocytic tumors, the tumor cells of which develop characteristic fine bipolar fibrillar processes and are called pilocytes (hair cells), which gives the tumor its name. Mitotic activity is low. Characteristic is the relatively sharp demarcation from the surrounding brain tissue and a biphasic growth pattern, with fiber-rich sections with numerous Rosenthal fibers and fiber-poor, microcystically loosened areas with so-called eosinophilic granular bodies alternate. These include tumors with a so-called pilomyxoid growth pattern, which are referred to as pilomyxoid astrocytoma and tend to recur more frequently, the rare malignant anaplastic pilocytic astrocytoma and diffuse astrocytic tumors such as fibrillar astrocytoma .

Treatment and course of the disease

After complete surgical removal of the tumor, which is usually quite possible, especially if it is in the area of ​​the cerebellum, the prognosis is favorable. If the tumor cannot be completely removed, the further course of the disease may be characterized by renewed tumor growth. However, especially in patients with neurofibromatosis type 1, the course is only slowly progressing over many years.

literature

• Scheithauer et al .: Pilocytic astrocytoma. In: WHO classification of tumors of the central nervous system. IARC Press, Lyon, 2007

Individual evidence

1. ↑ Burkhard et al .: A population-based study of the incidence and survival rates in patients with pilocytic astrocytoma. In: J Neurosurg. , 2003 Jun; 98 (6): 1170-4. PMID 12816259
2. ↑ Tihan et al .: Pediatric astrocytomas with monomorphous pilomyxoid features and a less favorable outcome. In: J Neuropathol Exp Neurol. , 1999; 58 (10): 1061-8. PMID 10515229

Web links

Commons : Pilocytic Astrocytoma  - Collection of Images, Videos, and Audio Files

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