Pituitary Adenoma

    • Tumor caused by neoplasia of the anterior pituitary gland
    • Young and middle-aged women are most affected
    • Visual loss is usually slow, but may be acute from tumor hemorrhage (“pituitary apoplexy”)
    • Most tumors that affect vision are endocrinologically silent
    • Brain MRI is often diagnostic, but…
    • Trap: other masses can mimic pituitary adenoma on MRI
    • Transsphenoidal surgery usually provides dramatic visual improvement, but…
    • Large extrasellar extension may pose extra surgical risk
    • Marked pre-operative vision impairment adversely affects visual outcome
    • Core clinical features
      • Subacute or chronic visual loss, often monocular
      • Sudden visual loss usually means tumor hemorrhage in “pituitary apoplexy”
      • Nerve fiber bundle and/or hemianopic defect
      • Afferent pupil defect
      • Optic discs appear normal or pale
    • Possible accompanying clinical features
      • Chronic or new headache
      • Hormonally-silent tumors are typically larger and more vision-impairing at presentation than the following hormonally-active tumors
        • Prolactin-secreting: galactorrhea, amenorrhea, decreased libido, impotence
        • Growth hormone-secreting: acromegaly, gigantism
        • Corticotrophin-secreting: cushingoid features, diabetes, myopathy
        • Thyrotropin-secreting: hyperthyroidism, goiter
        • Gonadotropin-secreting: precocious puberty, decreased libido
    • Imaging features
      • Avidly and homogeneously enhancing mass originating in the pituitary gland with extension into the suprasellar space
      • Belt-like constriction between the sellar and suprasellar components of the tumor because of a tight diaphragma sellae
    • Meningioma
    • Craniopharyngioma
    • Rathke cleft cyst
    • Pilocytic astrocytoma (Optic glioma)
    • Carotid aneurysm
    • Germinoma
    • Pituitary hyperplasia
    • Sinonasal cancer
    • Metastatic cancer
    • Arachnoid cyst
    • Epidermoid and dermoid cysts
    • Histiocytosis
    • Sphenoid sinusitis or mucocele
    • Lymphocytic hypophysitis
    • Pituitary abscess
    • Sarcoidosis
    • Order brain MRI
    • Trap: watch out for the following masses that mimic pituitary adenoma on MRI: pituitary hyperplasia, craniopharyngioma, metastasis, germ cell tumor, aneurysm, lymphocytic hypophysitis
    • Order serum prolactin: >200ng/ml signals a prolactinoma, which is usually treated first with a dopamine agonist (cabergoline)
    • Tip: non-prolactinoma sellar masses often elevate prolactin (“stalk effect”), but never above 200ng/ml
    • Refer non-prolactinomas to a neurosurgeon
    • Prolactinomas often shrink rapidly with dramatic visual improvement following dopamine agonist (cabergoline) therapy, making surgery unnecessary, but…
    • Trap: dopamine agonist therapy is not always effective or tolerated and must be maintained indefinitely
    • Non-prolactinomas are effectively managed by transsphenoidal or wide endonasal surgery with visual improvement or stabilization in >90%
    • If the tumor must be approached transcranially, visual improvement is less likely and visual damage is more likely
    • Tip: pituitary apoplexy must be managed with prompt hormonal replacement and fluids, but surgery can probably be briefly delayed without adverse consequences to allow for metabolic stabilization 
    • Regrowth of tumor is uncommon but may occur many years after initial treatment, so you must maintain imaging and clinical surveillance
    • Radiation therapy is reserved for non-candidates for surgery, large post-operative residual tumors, or tumor regrowth

    Optic Nerve And Chiasm Disorders

    Drusen Optic Neuropathy Colobomatous Optic Neuropathy Optic Pit Neuropathy Morning Glory Optic Neuropathy Hypoplastic Optic Neuropathy Typical Optic Neuritis Atypical Optic Neuritis Papillitis (Neuroretinitis) Non-arteritic Ischemic Optic Neuropathy Arteritic Ischemic Optic Neuropathy Posterior Ischemic Optic Neuropathy Hypotensive Ischemic Optic Neuropathy Radiation-induced Optic Neuropathy Diabetic Papillopathy Hypertensive Optic Disc Edema Papilledema Idiopathic Intracranial Hypertension (Pseudotumor Cerebri) Compressive Optic Neuropathy: Overview Optic Neuropathy of Graves Disease Optic Nerve Sheath Meningioma Sphenoid Meningioma Craniopharyngioma Pituitary Adenoma Pilocytic Astrocytoma (Optic Glioma) Carotid Aneurysm Suprasellar Germinoma Infiltrative (Neoplastic) Optic Neuropathy Paraneoplastic Optic Neuropathy Traumatic Optic Neuropathy Toxic Optic Neuropathy Nutritional Deficiency Optic Neuropathy Dominantly-Inherited Optic Neuropathy Leber Hereditary Optic Neuropathy Primary Open Angle Glaucoma