Pilocytic astrocytoma

The pilocytic astrocytoma is a slow-growing astrocytic brain tumor that occurs mainly in children and young adults and is the most common tumor in this age group. As histological benign tumor he is classified as grade I according to the WHO classification of tumors of the central nervous system.

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

Clinical manifestation

For localization of the tumor in the posterior cranial fossa are often disorders of cerebellar function as unsteady gait (ataxia) in the foreground, tumors of the diencephalon become noticeable among others with hypothalamic dysfunction. Are optic nerve or visual pathways affected, impaired vision and even blindness can occur.

Morphology

Macroscopically it is bulbous, firm tumors with gray- white cut surface, often with cystic components. Histologically it is astrocytic tumors whose tumor cells form characteristic fine fibrillar bipolar appendages and ( eponymous for the tumor ) as Pilozyten ( hair cells) are referred to. The mitotic activity is low. It is characterized by relatively sharp demarcation from the surrounding brain tissue as well as a biphasic growth pattern, with mikrozystisch alternate fiber-rich sections with numerous Rosenthal fibers and low in fiber loosened areas with so-called eosinophilic granular bodies. Delineate these, among other tumors with a so-called pilomyxoiden growth patterns that are called pilomyxoides astrocytoma and often tend to recur, the rare malignant anaplastic pilocytic astrocytoma and diffuse astrocytic tumors such as fibrillary astrocytoma.

Treatment and disease progression

After complete surgical removal of the tumor, which usually is quite possible especially when located in the cerebellum, the prognosis is favorable. Can not be completely removed, the tumor, the further course of the disease is characterized in certain circumstances by renewed tumor growth. Especially in patients with neurofibromatosis type 1, however, the course is slowly progressive over many years.