Primitive neuroectodermal tumor

As a primitive neuroectodermal tumor (abbreviation: PNET, English: primitive neuroectodermal tumor ), a tumor of the nerve tissue from the group of embryonal tumors is called. PNET occur predominantly in children and adolescents. A distinction is made between a central nervous system (brain or spinal cord) and one outside of it occurring, so-called peripheral variant. When malignant tumors are classified PNET of the brain according to the WHO classification of tumors of the central nervous system as grade IV.

Variants

PNET of the central nervous system ( CNS PNETs ). The first description of a PNET of the central nervous system was carried out in 1973 by Hart and Earle. Subject of their investigations were undifferentiated tumors of brain ( cerebral hemispheres ) above the cerebellar roof ( tentorium cerebelli ): this observation led to the common name supratentorial PNET (ST- PNET ). The PNET of the central nervous system exhibit histologic ( histology ) based on similarities to distinct medulloblastomas, Pinealoblastomen and other tumor types. Some investigators have taken this similarity as an opportunity to define the PNET as a summary group of embryonal tumors of the central nervous system: this view is disputed.

2.5-6 % of all brain tumors in childhood and adolescence are counted among the PNET of the central nervous system. If the medulloblastomas aggregated with PNET to a group ( as previously disputed), so, this combined group 20 % of brain tumors in childhood and adolescence dar.

Peripheral PNET ( pPNET ). Peripheral PNET are tumors that take their origin from ectodermal -derived parts of the body. This primarily includes the autonomic nervous system ( sympathetic and parasympathetic ). Peripheral PNET typically occur in the thoracic wall ( chest wall ): they are then referred to as Askin tumors. Other localizations are known: kidney, lung, uterus, ovary, testis, pancreas, urinary bladder, parotid gland, skin and subcutaneous fat have been described in conjunction with peripheral PNET as localization.

The delineation of peripheral PNET Ewing 's sarcoma is not easy: see some investigators Ewing's sarcoma as a subset of peripheral PNET.

Symptoms

The symptoms are derived mainly from the position ( location ) of the PNET. PNET of the central nervous system are characterized by symptoms such as nausea and vomiting (especially sober and morning) conspicuous. At the losses may occur from skills ( paralysis, visual disturbances, personality changes ) caused by neurological deficits ( loss of nerve functions) are explained. Peripheral PNET can be noticed only as swelling depending on the location first. In a situation inside the body ( for example, lung ) occur shortness of breath or coughing up blood. Peripheral PNET of the ovary, pancreas and uterus will be felt first by abdominal pain.

Diagnostics

The pioneering diagnosis is usually done through a histological (histological ) examination after sampling (biopsy) or removal of the PNET (resection by surgery). The latter may occur especially in PNET in the central nervous system only partially or not at all be possible.

Before sampling or surgery, the use of imaging techniques such as ultrasound (sonography), computed tomography and magnetic resonance imaging is performed. All these methods have in common is that they can provide information on the extent and spread of PNET. A reliable diagnosis of a PNET alone imaging is not possible.

Therapy

First, you should - if possible - a surgical removal or at least one sampling to confirm the diagnosis be attempted. This is particularly the case with the peripheral PNET. Following the sampling or surgery always occurs in childhood and adolescence under polychemotherapy combination of different cytostatics. Radiotherapy also is used.

In PNET, which are classified as high-risk PNET or the inadequate response to the primary treatment, high-dose chemotherapy followed by autologous stem cell transplantation is carried out mostly.

Forecast

The prognosis of PNET is very different depending on their location, the operability and the age of the patient. In the middle of all those affected the prognosis of PNET with a 5 -year survival of 53 % is classified as average.