HYPOTHALAMIC, PITUITARY AND OTHER SELLAR MASSES

Pituitary tumors , Pituitary adenomas   :

• Commonest tumors are pitu­itary adenomas. These are benign and their features depend on the cell type from which they occur.
• They may arise from PRL, GH, ACTH, TSH, LH and FSH producing cells r;esulting in features of hyperse­cretion of the hormones.
• There is autonomous hormone secretion which does not respond to the inhibitory feedback of these hor­mone levels.
• Many of these tumors do not produce hypersecretion features.

HYPOTHALAMIC, PITUITARY AND OTHER SELLAR MASSES

Causes of sellar masses

• Arachnoid

  Benign tumors

  Breast

  Carotid arteriovenous fistula

  Chordoma

  Craniopharyngioma

  Cysts

  Dermoid

  Germ cell tumor (ectopic pinealoma)

  Lactotroph hyperplasia (during pregnancy)

  Lung

  Lymphocytic hypophysitis

  Malignant tumors

  Meningiomas

  Metastatic

  Pituitary abscess

  Pituitary adenoma (most common sellar mass)

  Pituitary carcinoma (rare)

  Pituitary hyperplasia

  Primary

  Rathke’s cleft

  Sarcoma

  Somatotroph hyperplasia due to ectopic GHRH

  Thyrotroph and gonadotroph hyperplasia

Other neurologic symptoms —

• Cerebrospinal fluid rhinorrhea, caused by inferior extension of the adenoma, is an extremely uncommon presentation.
• Diplopia, induced by oculomotor nerve compression resulting from lateral extension of the adenoma.
• Headaches, presumably caused by expansion of the sella. The quality of the headache is not specific.
• Other neurologic symptoms that may cause a patient with a sellar mass to seek medical attention include:
• Parinaud syndrome, a constellation of neuroophthalmologic findings, most often paralysis of upward conjugate gaze, that result from ectopic pinealomas
• Pituitary apoplexy induced by sudden hemorrhage into the adenoma, causing excruciating headache and diplopia.

Pituitary carcinoma is rare. Craniopharyngiomas :

• These are derived from Rathke’s pouch. They arise near the pituitary stalk and extend to supracellar region.
• They are large, cystic and locally invasive.
• They may be calcified and seen on x-ray and CT. Age of presentation is less than 20 years.
• There is raised intracranial pressure with headache, vomiting, papilledema, hydrocephalus, visual field de­fects, cranial nerve damage, weight gain, personality changes, growth retardation.
• There may also be diabetes insipidus (if the posterior pituitary is involved).

Treatment of pituitary masses

• Surgical resection and radiation after surgery. Patients may require lifelong pituitary hormone replacement.

Other tumors :

• Meningiomas, Histiocytosis X, Glio­mas, Germinomas may also occur.

Lab diagnosis of tumors and masses

• · MRI, CT, visual field examination and other im­aging techniques.
• · Histopathologic diagnosis of tumor after surgery.
• · Hormonal evaluation:

1. 1. Basal PRL (prolactin)
2. 2. IGF (insulin like growth factor)
3. 3. 24-hour urinary free cortisol (UFC and or over­night oral dexamethasone 1 mg suppression test)
4. 4. FSH and LH levels
5. 5. Thyroid function tests.

Treatment of hypothalamic and pituitary masses

• Transsphenoidal surgery
• Stereotactic radiotherapy (gamma knife radio­therapy)
• Radiation
• Bromocriptine, the Dopamine agonist for hyperprolactinemia
• Estrogen replacement for bone loss and hypoestrogenem ia
• Growth hormone
• Thyroxine etc.