| How do pituitary tumors impinge on optic chiasm? | Optic chiasm is just above the pituitary, a tumor will pressure temporal visual fields, starting superiorly and extending to the whole field, can extend to visual loss and blindness.
Long standing pressure results in optic disc pallor (damage) |
| What are the complications of pituitary lesions extending laterally? | May impinge dural wall of cavernous sinus, affects 3rd, 4th and 6th cranial nerves and ophthalmic and maxillary branches of 5th CN
can cause diplopia, ptosis, opthalmopelgia, decreased facial sensation. |
| What are the complications of pituitary lesions extending downwards? | May erode bony sellar floor, invade roof of palate and cause nasopharygeal obstruction, infection or leakage of CSF |
| What pituitary lesions cause headaches? | Microadenoma (change in intrasellar pressure, stretch of dural plate)
The size of adenoma is not associated with the headache severity, minor dural impingement may be associated with persistent headache. Successful management of small pituitary tumors improve headache |
| What is hypopituitarism? | Pitutiary mass compressing healthy tissue, like stalk compression causing pituitary failure |
| What are the effects of pituitary masses compressing each part of the surrounding? | Pituitary (pan failure)
Optic tract (loss of red perception, blindness...)
Hypothalamus (temp dysregulation, obesity, DI, sleep, thirst and apetite)
Cavernous sinus (ptosis, diplopia, ophthalmoplegia...)
temporal lobe (seizures)
Frontal lobe (personality disorder or anosmia)
Central (headache...) |
| How do we evaluate pituitary masses? | 90% of sellar masses are pituitary adenomas and 10 % are rare lesions.
Adenomas may arise from differentiated cells (may be secreting or non-secreting)
So we see if mass is hormonally functional or not and evaluate local mass effects
It is imp to note that incidentalomas occur 20% of the times, and pituitary adenomas take years to be symptomatic |
| What are the 4 types of parasellar masses? | Rathke's cyst, Craniopharyngioma, Meningioma, and gliomas |
| What is Rathke's cyst? | Cyst between ant and post pituitary arise embryologically from rathke's pouch
20% of pituitary glands at autopsy, may extend to suprasellar region, mostly asymptomatic (rarely with panhypopituitarism with or without DI)
May cause headache or visual disturbance acc to its size and location
After removal we follow up signs of recurrence and evaluate hypopituitarism |
| What are Craniopharyngiomas? | 10% of childhood brain tumors, bimodal age (5-14 or 50-75 years), embryonic squamous remnant of rathke's pouch, may be large (>10cm) and invade third ventricle.
Cystic mass (rich in cholesterol, calcification, hCG, squamous epithelium islands)
Increase intracranial pressure (headache, projectile vomiting, papilledema, somnolence) for children
For adults visual disturbance, and cavernous sinus involvement |
| What are meningiomas? | Arise from arachnoid and meningoendothelial cells, secondary hyperprolactinemia, and can cause local mass headache, visual disturbance and optic atrophy. |
| What are gliomas? | Optic gliomas or low grade astrocytomas in optic chiasm or optic tract infiltrating optic nerve |
| What are parasellar aneurysms? | May mimic a pituitary adenoma, cause eye pain, intense headache, cranial nerve palsies sudden onset |
| What is metastasis to pituitary region? | Blood borne metastatic spread goes from posterior pituitary, mostly breast, lung and GI lesions, with DI and may mimic adenoma on imaging |
| What is lymphocytic hypophysitis? | Autoimmune inflammatory disorder, 60% association with pregnancy, isolated or associated with endocrinopathies
May occur with pituitary hormone deficiency, or secondary adenohypophyseal cell atrophy with resultant empty sella (filled with CSF) |
| What are the clinical features of lymphycytic hypophysitis? | Pituitary enlargement, headache and visual disturbance, hypopituitarism, hyperprolactinemia, secondary adrenal insufficiency, DI |
| What is the pathology and prognosis of lymphocytic hypophysitis? | Pituitary cell islands surrounded by lymphocytic infltrates (T and B cells)
Circulating anti pituitary antibodies, MRI similar to adenoma and empty sella
Prognosis inflammation resolves with time and pituitary function may be restored or chronically compromised |
| What is hemorrhage and infarction pituitary masses? | Ischemic damage to hypophyseal portal system, mostly limited to the anterior lobe, causing pituitary insufficiency after 75% of the gland is chemically damaged and can cause significant life-threatening damage |
| What is pituitary apoplexy? | Spontaneous hemorrhage into pituitary adenoma after trauma or skull base fracture, associated with HTN and DI, SCA or hypovolemic shock.
Precipitating factors: surgery, pregnancy, gamma knife irradiation, AG therapy, live failure, pituitary meds |
| What are the clinical features of apoplexy? | Endocrine emergency, evolve over 1-2 days, severe headaches or ocular palsies or visual field defects.
Cardiovascular collapse, change in consciousness, neck stiffness and hypoglycemia
Acute adrenal insufficiency
CT or MRI reveals intrapituitary hemorrhage, stalk deviation and pituitary compression |
| What is Sheehan's syndrome? | Post partum pituitary infarction, increase estrogen stimulation enlarges the pituitary, hypervascular gland leading to vulnerability to arterial pressure change and prone to hemorrhage, hypovolemic shock causing necrosis and fast onset hypopituitarism
Signs are inability to nurse and postpartum amenorrhea
May be caused by autoimmunity |
| What are other lesions of the pituitary? | Hematologic malignancy (B cell non hodgkins)
Sarcoidosis
Iron storage disease (hemochromatosis and hemosiderosis causing gonadotroph cell damage) |
