Meeting ID: 949 4596 2548
It is estimated that 5% of pituitary adenoma become invasive and may grow to gigantic sizes (>4 cm in diameter).
They are mostly clinically non-functioning adenomas and occur predominantly in males 1)
see also Giant somatotroph adenoma.
The presenting symptoms are usually secondary to compression of neighboring structures, but also due to partial or total hypopituitarism. Functioning pituitary adenomas give rise to specific symptoms of hormonal hypersecretion.
The use of dopamine agonists is considered a first-line treatment in patients with giant macroprolactinomas. Somatostatin analogs can also be used as primary treatment in cases of growth hormone and thyrotropin producing giant adenomas, although remission of the disease is not achieved in the vast majority of these patients.
The intrinsic complexity of these tumors requires the use of different therapies in a combined or sequential way. A multimodal approach and a therapeutic strategy involving a multidisciplinary team of expert professionals form the basis of the therapeutic success in these patients 2).
The main goal of surgical treatment of giant pituitary adenoma is maximum possible tumor extirpation with minimal side effects, which can be achieved by careful preoperative planning of operative approach, based on directions of tumor extensions and invasiveness. Maximal surgical removal of giant adenomas offers best chances to control tumor growth when followed with adjuvant medical and radiation therapies 3).
While the use of endoscopic approaches has become increasingly accepted in the resection of pituitary adenomas, limited evidence exists regarding the success of this technique for patients with large and giant pituitary adenomas.
Major blood supply of giant pituitary adenomas originates from branches of the infraclinoidal portion of the internal carotid artery, different from normal anterior pituitary gland. Surgical route should depend not only on tumor shape and extension but on feeding systems 4).
The main goal of surgical treatment of giant pituitary adenoma is maximum possible tumor extirpation with minimal side effects, which can be achieved by careful preoperative planning of operative approach, based on directions of tumor extensions and invasiveness. Maximal surgical removal of giant adenomas offers best chances to control tumor growth when followed with adjuvant medical and radiation therapies 5).
In cases of progressive enlargement of residual lesions, a second endoscopic debulking of the tumor may be considered for control of the disease 6).
Giant pituitary adenomas carry higher surgical risks despite recent advances in microsurgical and/or endoscopic surgery, and postoperative acute catastrophic changes without major vessel disturbance are still extremely difficult to predict, may manifest as postoperative pituitary apoplexy, and are associated with very poor outcomes.
Optimal pituitary apoplexy management remains controversial.
The pituitary function is consistently compromised, necessitating rapid administration of corticosteroids and endocrine evaluation.
Patients with pituitary apoplexy may have a spontaneous remission of hormonal hypersecretion. If it is not an emergency, we should delay a decision to undertake surgery following apoplexy and re-evaluate hormone secretion. Hyponatremia is an acute sign of hypocortisolism in pituitary apoplexy. However, SIADH although uncommon, could appear later as a consequence of direct hypothalamic insult and requires active and individualized treatment. For this reason, closely monitoring sodium at the beginning of the episode and throughout the first week is advisable to guard against SIADH. Despite being less frequent, if pituitary apoplexy is limited to the tumor, the patient can recover pituitary function previously damaged by the undiagnosed macroadenoma 1).
Rapid decompression is required for: sudden constriction of visual fields, severe and/or rapid deterioration of acuity, or neurologic deterioration due to hydrocephalus. Surgery in ≤7 days of pituitary apoplexy resulted in better improvement in ophthalmoplegia (100%), visual acuity (88%) and field cuts (95%) than surgery after 7 days, based on a retrospective study of 37 patients. 2).
Decompression is usually via a transsphenoidal route (transcranial approach may be advantageous in some cases).
A systematic literature search was performed of MedLine, Embase, the Cochrane Library, and the Web of Science for articles published between January 1992 and September 2014. Studies of the outcomes in consecutive patients that compared surgical intervention with non-surgical treatment for pituitary apoplexy were included.
Six studies met the inclusion criteria. As compared to the non-surgically treated patients, surgically treated patients had a significantly higher rate of recovery of ocular palsy and visual field (both P<0.05). However, there was no significant difference in the recovery of visual acuity and pituitary function (P>0.05) between the two groups.
The findings of this study suggest that surgical intervention should be advocated for pituitary apoplexy patients with visual field defects and ocular palsy 3).
2. Obtain tissue for pathology
3. Complete removal of the tumor is usually not necessary
4. For hydrocephalus: ventricular drainage is generally required.