•Neuroendocrine sequelae are infrequent after chemotherapy in contrast to those after radiotherapy

•Effective drugs: see above, under Characteristics of low-grade astrocytoma (LGA I and II)

•In tumor progression after chemotherapy, irradiation is indicated

•Radiotherapy: reduction of tumor mass and arrest of visual loss in patient with low-grade classification (see “Astrocytic Tumors”)

•Prognosis: a slow, progressive tumor with high morbidity (loss of vision, panhypopituitarism, diabetes insipidus, involvement of brain nerves)

9.12.3Brain Stem Tumors

9.12.3.1 Incidence

• Fifteen to twenty-five percent of all brain tumors in children, including those with neurofibromatosis

• Mostly in children between 3 and 9 years of age

9.12.3.2 Pathology

•Often a large infiltrating tumor at time of first symptoms

•Rarely, blockade of circulation of the cerebral fluid, usually inoperable; biopsy with high risk of complications depending on tumor location

•Histologically astrocytomas (two-thirds, grades I and II; one-third, grades III and IV)

•Rarely embryonic histology, i.e., primitive neuroectodermal tumor (PNET) or hemangioblastoma

9.12.3.3 Location

• Mainly in the pons, occasionally in the medulla oblongata or the midbrain

9.12.3.4 Clinical Manifestations

•Diplopia

•Deficiency of abducens nerve (inability to abduct one or both eyes)

•Ataxia (sign of involvement of cerebellum)

•Involvement of medulla oblongata: dysarthria, dysphagia, deficit of the lower cranial nerves

•Sensory deficit mostly limited to the face (involvement of trigeminal nerve)

•Disturbances of gait

9.12.3.5 Radiological Diagnosis

MRI/CT findings:

•Enlarged, hypodense brain stem with or without cysts

•Fourth ventricle in caudal position

•Often mild hydrocephalus, consider differential diagnosis of cystic lesions, which indicate different prognosis and histology