Giant pituitary adenomas: clinical characteristics and surgical results

Abstract

Although most pituitary neoplasms are benign, some grow rapidly, spreading to extrasellar tissues. Definition of these 'giant' pituitary adenomas (PAs) is not clear. In order to clarify this question, we studied all pituitary macroadenomas operated in our hospital during the last 20 years, differentiating those with diameter > or = 3 cm (n = 43) and attempting to identify their typical features and prognosis. The reason for consultation was local in 58.3% of giant PAs, hormonal in 22.9% and tumour recurrence in 16.7%. Surgery was performed via a trans-sphenoidal approach in 92.5% of cases and succeeded in completely removing the tumour in only 27% of cases. In conclusion, we found that giant PAs are not a special type but the extreme case in the gradient of invasiveness of tumours of adenohypophyseal origin. They are characterized by a higher frequency of neuro-ophthalmological symptoms and hormonal deficits, and poorer response to surgical treatment.

Intraoperative magnetic resonance imaging-guided transsphenoidal surgery for giant pituitary adenomas

“…The most frequent postoperative complications include transient diabetes insipidus (DI) in 3.7% to 18.8% and CSF leak with meningitis in 7.4% to 14.6% [8,9]. In one study, these complications were not significantly more frequent than in non-giant PAs [8].…”

“…Patients with GPAs compared to patients with non-GPAs [8] more frequently present clinically with visual symptoms and headaches than hormonal disturbances [1,8,9,12,14]. Most GPAs are non-secreting, followed by growth hormone (GH) secretion and prolactinomas [1,8,10,12,14]. Radiologically, these tumors show more aggressive behavior with cavernous sinus (CS), skull base, and paranasal sinus invasion.…”

“…Hardy's classification groups PAs into four types, according to qualitative extensions [11,14]. Other authors define GPAs as tumors ≥30 mm in diameter [1,8], as ≥40 mm in diameter [9,10,19], or as tumors extending more than 40 mm from the midpoint of the jugum sphenoidale or to within 6 mm of the interventricular foramen [7,12,18]. Patients with GPAs compared to patients with non-GPAs [8] more frequently present clinically with visual symptoms and headaches than hormonal disturbances [1,8,9,12,14].…”

“…Radiologically, these tumors show more aggressive behavior with cavernous sinus (CS), skull base, and paranasal sinus invasion. Invasion or infiltration is not confined to a selected adenoma size or diameter and varies according to literature from 9 to 40%, but is more prevalent with larger tumors [8,16]. Additionally, GPAs can cause occlusive hydrocephalus by impairment of cerebrospinal fluid (CSF) drainage [12].…”

“…Between 27.9% and 40% of tumors are excised totally according to several reports [1,8,9], and surgery can improve the primary symptom of the patient, diminished vision, in 65% to 90% [1,9].…”