Benign and malignant intra-axial tumors of the MESENCEPHALON; PONS; or MEDULLA OBLONGATA of the BRAIN STEM. Primary and metastatic neoplasms may occur in this location. Clinical features include ATAXIA, cranial neuropathies (see CRANIAL NERVE DISEASES), NAUSEA, hemiparesis (see HEMIPLEGIA), and quadriparesis. Primary brain stem neoplasms are more frequent in children. Histologic subtypes include GLIOMA; HEMANGIOBLASTOMA; GANGLIOGLIOMA; and EPENDYMOMA.

Synonyms: Tumors, Medullary, Tumors, Midbrain, Tumor, Pontine, Mesencephalic Neoplasms, Tumor, Brain Stem, Brain Stem Neoplasms, Pontine Tumor, Medullary Neoplasms, Mesencephalic Neoplasm, Brainstem Neoplasm, Neoplasm, Pontine, Pontine Tumors, Neoplasm, Mesencephalic, Neoplasm, Midbrain, Primary Brain Stem Neoplasms, Pontine Neoplasm, Tumors, Pontine, Brainstem Tumors, Midbrain Tumor, Brain Stem Tumors, Tumor, Medullary, Brain Stem Neoplasm, Brain Stem Neoplasms, Primary, Brain Stem Tumor, Tumor, Midbrain, Neoplasm, Medullary, Midbrain Neoplasm, Neoplasms, Brainstem, Brainstem Neoplasms, Neoplasms, Midbrain, Primary Brainstem Neoplasm, Neoplasm, Brainstem, Neoplasms, Medullary, Pontine Neoplasms, Neoplasms, Primary Brainstem, Neoplasm, Primary Brainstem, Medullary Tumor, Neoplasms, Mesencephalic, Brainstem Tumor, Medullary Tumors, Brainstem Neoplasm, Primary, Neoplasms, Brain Stem, Medullary Neoplasm, Brainstem Neoplasms, Primary, Midbrain Tumors, Primary Brainstem Neoplasms, Neoplasm, Brain Stem, Neoplasms, Brainstem, Primary, Midbrain Neoplasms, Neoplasms, Pontine