Medulloblastoma

Medulloblastoma is a malignant embryonal tumor of the cerebellum. It tends to occur in infant and childhood, and in this age group the most common malignant brain tumor. It is classified according to the WHO classification of tumors of the central nervous system as grade IV.

Symptoms

Clinically most disorders of cerebellar function (eg, tendency to fall, and ataxia ), and signs of increased intracranial pressure with headache, lethargy and vomiting morgendlichem in the foreground. In reflection of the fundus a papilledema can be detected.

Imaging

Computed tomography and magnetic resonance imaging ( MRI) to provide medulloblastomas as solid masses with homogeneous contrast enhancement dar.

Pathology

Histologically, medulloblastomas are cell-density small -round- and blauzellige tumors. The tumor cells have round to oval nuclei and can be arranged in rosette formations. Immunohistochemistry is an expression of neuronal markers ( synaptophysin, neurofilament, NeuN ) typical but also glial proteins such as GFAP can be expressed in small areas. Delineate When variants are desmoplastic medulloblastoma, anaplastic medulloblastoma and medulloblastoma with extensive nodularity.

Genetics

The first evidence of a p53 mutation in a medulloblastoma was made in the early nineties. Currently, medulloblastomas are divided into the following four subgroups based on their genetic profile:

• WNT: mostly children, rarely Adults: monosomy chromosome 6, CTNNB1 mutations, mostly classic medulloblastomas, rare large cell / anaplastic medulloblastomas. This group has the best prognosis.
• SHH: Infants ( usually desmoplastisch / nodular ) and adults ( classic or large cell / anaplastic ): PTCH / SMO / SUFU mutations, GLI2 amplifications.
• Group 3: mostly children, classic medulloblastomas, often metastasizing, MYC Amplifiaktion, Chromosomal losses on 5q and 10q. This group has the worst prognosis.
• Group 4: mostly children, more often male, often isochromosome 17q. Chromosomal losses at 8 and X.

Therapy

Current treatment approaches for children and adolescents with medulloblastoma provide a neurosurgical tumor resection, chemotherapy and radiotherapy.

Forecast

The course of the disease depends on, among other things, on the tumor size, the extent of removal of the tumor, tumor cells of any delocalization along CSF pathways and the patient's age. The type of histological differentiation may play a prognostic role, which is more favorable with a so-called medulloblastoma desmoplastischem the course of disease in patients.

In a recent clinical study, the 5 - year survival rate was 66 % in children with medulloblastoma who were chemo intensive treatment after diagnosis only. After complete removal of the tumor was a 5 - year survival rate of 93 % can be achieved here. According to incomplete tumor removal or resettlement of tumor cells along CSF 5- year survival rates were 56 % and 38 %.