Infrasellar Extension of Pituitary Macro-Adenomas

Abstract
Background: Growth patterns of pituitary adenomas have been observed to vary according to the histopathological subtype.
Aim of Study: The authors aimed to analyse infrasellar extension pattern in cases of functional and non-functional macroadenomas.
Patients and Methods: Retrospective analysis of pituitary adenoma patients who underwent endoscopic trans-sphenoidal surgery in the time period between 2007 and 2013 at our institute. Patients with microadenomas and prior operations were excluded from the analysis. Preoperative MR images were reviewed to assess patterns of extrasellar extension in the varying tumor subtypes.
Results: The cohort comprised 150 patients, after exclusion of microadenomas and previously operated patients, the analysis involved 93 cases. Most of the cases were non-functional macroadenomas (66 patients, 71%), the remaining were functional macroadenomas (GH-macroadenoma: 17 patients, 18%; Macroprolactinoma: 8 patients, 9%; TSH-producing macroadenoma: 1 patient, 1%; and ACTH-cell macroadenoma: 1 patient, 1%). Extension of the non-functional macroadenomas occurred into the following regions: Supra-sellar, 63 patients (96%); infrasellar, 11 patients (17%); and parasellar, 17 patients (26%). Extension of the GH-mac-roadenomas occurred into the following regions: Suprasellar, 7 patients (41%); infrasellar, 9 patients (53%); and parasellar, 3 patients (18%). Extension of macroprolactinomas occurred into the following regions: Suprasellar, 8 patients (100%); infrasellar, 2 patients (25%); and parasellar, 4 patients (50%). Isolated infrasellar extension was noticed in 8 patients with GH-macroadenoma (47%) and in 2 patients with non-functional macroadenoma (3%). GH-macroadenomas had higher overall rates of infrasellar extension (53%, p<0.05), and isolated infrasellar extension (47%, p<0.05).
Conclusions: Extrasellar growth patterns in cases of pituitary macroadenoma showed substantial differences in relation to histological subtypes. GH-macroadenomas dem-onstrated a tendency for infrasellar extension. Existing data suggests lower surgical cure rates in adenomas with infrasellar extension. This fact may contribute particularly to the low normalisation rate after GH-adenoma surgery. If adaption of surgical technique may lead to better results, should be addressed in prospective studies.