#3. Recognize specific syndromes; extra-axial (cerebellopontine, pituitary, frontal) and intra-axial in brain tumor presentation

Extra-axial Tumors Extrinsic to the brain include meningiomas, schwannomas, neurofibromas, and pituitary tumors, craniopharyngiomas as well as mesenchymal tumors of the skull, spine, and dura mater

Meningioma Derived from arachnoid cap cells of the arachnoid mater Appear to arise from the dura mater grossly and on MRI: “dural based tumors” Most common intracranial locations: along the falx cerebri , the convexities and the sphenoid wing. Less common locations: foramen magnum, olfactory groove, and inside the lateral ventricle

Meningioma Mostly slow growing, encapsulated, and benign Malignant  may invade adjacent bone or into the cortex Previous cranial irradiation: risk Tx: Total resection, post op radiation (atypical and malignant melanoma)

Postcontrast T1-weighted coronal MRI demonstrating a brightly enhancing lesion arising from the falx cerebri with moderate edema and mass effect on the right lateral ventricle. This is a falcine meningioma. Note also the small separate meningioma arising from the dura over the cerebral convexity.

Vestibular Schwannoma (Acoustic Neuroma) Arise from the superior half of the vestibular portion of the vestibulocochlear nerve (CN VIII) commonly present with progressive hearing loss, tinnitus, or balance difficulty Large tumors may cause brain stem compression and obstructive hydrocephalus Bilateral acoustic neuromas are pathognomonic for neurofibromatosis type 2, a syndrome resulting from chromosome 22 mutation.

Vestibular Schwannoma (Acoustic Neuroma) Tx: microsurgical resection or with conformal stereotactic radiosurgery (gamma knife or linear accelerator technology) Complication: damage to the facial nerve (cranial nerve VII)

A. Postcontrast T1-weighted axial MRI demonstrating a brightly enhancing mass on the right vestibular nerve with an enhancing tail going into the internal auditory canal (arrowhead). Pathology demonstrated vestibular schwannoma

Pituitary Adenoma arise from the anterior pituitary gland (the adenohypophysis). Microadenoma: <1cm; Macroadenoma >1 cm Functional (i.e., secrete endocrinologically active compounds at pathologic levels) or nonfunctional (i.e., secrete nothing or inactive compounds). The most common endocrine syndromes are Cushing's disease due to adrenocorticotropic hormone (ACTH) secretion, Forbes-Albright syndrome due to prolactin secretion, and acromegaly due to growth hormone secretion.

Pituitary Adenoma Nonfunctional tumors commonly present when larger due to mass effect. Common symptoms : visual field deficits due to compression of the optic chiasm, or panhypopituitarism due to compression of the gland. Tx: Surgery (Transphenoidal), medical (Prolactinomas)

Postcontrast T1-weighted sagittal MRI demonstrating a large sellar/suprasellar lesion involving the third ventricle superiorly, and abutting the midbrain and pons posteriorly. The patient presented with progressive visual field and acuity loss. Pathology and lab work revealed a nonfunctioning pituitary adenoma.

Hemangioblastoma occur almost exclusively in the posterior fossa. Twenty percent occur in patients with von Hippel-Lindau (VHL) disease, a multisystem neoplastic disorder Appears as cystic tumors with an enhancing tumor on the cyst wall known as the mural nodule. Surgical resection is curative for sporadic (non-VHL associated) tumors.

Craniopharyngioma Benign cystic lesions that occur most frequently in children. Second peak of occurrence around 50 years of age. Symptoms result from compression of adjacent structures, especially the optic chiasm, pituitary or hypothalamic dysfunction or hydrocephalus may develop. Treatment is primarily surgical Complications: Visual loss, pituitary endocrine hypofunction, diabetes insipidus, and cognitive impairment from basal frontal injury

Neurofibroma more fusiform and grow within the parent nerve, rather than forming an encapsulated mass off the nerve, as with schwannomas. They are benign but not encapsulated. They present similarly to schwannomas and the two may be difficult to differentiate on imaging. Patients with multiple neurofibromas likely have neurofibromatosis type 1, also known as von Recklinghausen's neurofibromatosis. Resection for symptomatic lesions should be offered.