Disorders Chiasm• 3 SECTIONor Nerve Optic Acquired
Craniopharyngioma
Key Facts
•Benign partially cystic congenital tumor originating in sella turcica from remnants of pharyngeal epithelium
•May cause clinical symptoms at any age
•Brain MRI is often diagnostic
•Treat with cautious resection followed by radiation
•Recurrent visual loss from tumor cyst formation is common
Clinical Findings
•Reduced visual acuity and/or visual field (hemianopic defect in at least one eye)
•In children, visual loss sometimes accompanied by headache, hypopituitarism (especially growth retardation), papilledema, ventriculomegaly, and increased intracranial pressure
•In adults, visual loss is the principal symptom but hypopituitarism may occur
•Afferent pupil defect is common
•Temporal hemianopic defects are common
•Optic discs may appear normal, swollen, small, or pale
Ancillary Testing
•Brain imaging may be diagnostic in showing mass with heterogeneous signal high on T1 sequences
•Blood tests may show hypopituitarism
Differential Diagnosis
•Other mass lesions of sellar region (pituitary adenoma, aneurysm, meningioma, germinoma, dermoid or epidermoid, arachnoid cyst, optic glioma, metastatic cancer, multiple myeloma, chordoma, chondrosarcoma, vascular malformations, histiocytosis, primitive neuroectodermal tumor, lymphoma)
•Sphenoid sinusitis or mucocele
•Lymphocytic hypophysitis
•Pituitary abscess
•Multiple sclerosis
•Sarcoidosis
•Radiation damage
Treatment
• Transcranial cautious resection and decompression of cysts
• Ventriculoperitoneal shunt for unremitting hydrocephalus
• Postoperative high-dose radiation
Prognosis
• Natural history is progressive visual loss from further tumor growth
• Surgery occasionally improves vision, especially if cysts are decompressed
• Main purpose is to provide reduced tumor burden so that radiation may be more effective
• Aggressive resections associated with permanent worsening of vision
• Radiation doses >5000 cGy are necessary to prevent further tumor growth but place patient at risk for radiation optic neuropathy (see Radiation optic neuropathy) and other intracranial radiation complications
• Acute visual loss relapses resulting from cyst expansion can often be surgically
decompressed but may require permanent drain or radionuclide ablation
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Fig. 3.25 Craniopharyngioma. Precontrast coronal T1 MRI shows an inhomogeneous high signal from a dumbbellshaped mass (arrow). The high signal is caused by the high protein content within this tumor.
Craniopharyngioma
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Disorders Chiasm• 3 SECTIONor Nerve Optic Acquired
Pituitary Adenoma
Key Facts
•Benign tumor caused by hyperplasia of anterior pituitary cells • Young and middle-aged women most at risk • Visual loss usually slow • Sudden expansion of tumor by hemorrhage (pituitary apoplexy) can produce devastating visual loss and rarely death • Most tumors are endocrinologically silent, so visual loss is only symptom • Brain MRI may be diagnostic • Surgery (usually by trans-sphenoidal route) often provides visual improvement • Visual outcome is worse when preoperative visual loss is marked and tumors are extensive
Clinical Findings
•Chronic or subacute visual loss, usually monocular • Sudden visual loss in pituitary apoplexy • Chronic or new headache in 50%
•Endocrine function usually normal (two-thirds) but may be abnormal Prolactin-secreting: • galactorrhea or amenorrhea • decreased libido
• impotence
Growth hormone-secreting: • acromegaly • gigantism Adrenocorticotropin-secreting: • cushingoid features • diabetes • myopathy Thyrotropin-secreting: • hyperthyroidism • goiter
Gonadotropin-secreting: • precocious puberty • decreased libido
•Hemianopic defects are common • Afferent pupil defect is common • Optic discs appear normal or pale
Ancillary Testing
•Brain imaging often diagnostic • Serum tests may show hypopituitarism in
hormonally inactive tumors and selective hyperpituitarism in hormonally active tumors • Serum prolactin >200 ng/mL signals prolactinoma
Differential Diagnosis
•Other sellar region masses (craniopharyngioma, aneurysm, meningioma, germinoma, dermoid or epidermoid, optic glioma, metastatic cancer, multiple
myeloma, chordoma, vascular malformations, histiocytosis, primitive neuroectodermal tumor) • Sphenoid sinusitis or mucocele • Lymphocytic hypophysitis • Pituitary abscess • Multiple sclerosis • Sarcoidosis
• Radiation damage
Treatment
•Correct hypopituitarism
•For prolactinoma, treat first with low-dose dopamine agonist (bromocriptine, cabergoline)
•If unresponsive or patient is intolerant to medication, perform trans-sphenoidal surgery
•For non-prolactinomas, perform trans-sphenoidal surgery even if the tumor is large but has not extended far beyond the sella, otherwise perform transcranial surgery
•Radiation may be used if tumors cannot be managed surgically, if surgery leaves behind substantial tumor, or if there is late regrowth after surgery
Prognosis
•Prolactinomas: dopamine agonist therapy often dramatically shrinks tumor and reverses visual loss • Other pituitary adenomas: trans-sphenoidal surgery by experts is generally safe and produces visual improvement in 50%, stabilization in 40%, and worsening in only 10% • If tumor must be approached transcranially, chance of visual recovery is diminished • Late regrowth of tumor is associated with a poor visual outcome
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Fig. 3.26 Pituitary tumor with extrasellar extension. Postcontrast coronal T1 MRI shows a large high-signal mass that elevates and displaces the optic chiasm (arrow) and extends laterally into both cavernous sinuses (arrowheads).
A B
Fig. 3.27 Pituitary tumor with recent hemorrhage (pituitary apoplexy).
(A) Precontrast axial CT shows round mass in suprasellar cistern with a central bright (high attenuation) area indicating blood (arrow). (B) Precontrast sagittal T1 MRI shows a high-signal mass indicative of fresh blood in a tumor.
Adenoma Pituitary
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