Endocrine Abstracts

Giant pituitary adenomas present significant surgical challenges due to their size, invasive intracranial growth, and involvement of critical neurovascular structures. No consensus exists on the optimal surgical approach, often requiring multi-staged treatments. Most non-functioning adenomas measure 1–4 cm, with tumours over 4 cm being rare (10–15%). Tumours larger than 6 cm are classified as giant, while those exceeding 8 cm are extremely rare. Their asymptomatic, slow growth often leads to late presentation from mass effects. An 82-year-old male presented in 2009 with vision loss caused by a non-functioning pituitary macroadenoma (3x3.8x2.5 cm). Initial transsphenoidal surgery left a large residual mass in the sphenoid sinus and pituitary fossa, with mild chiasmal elevation. A second surgery, via a transoral/transmaxillary approach and palate splitting, significantly reduced the tumour. Follow-up showed stable MRI, visual fields, and no endocrine deficiencies. Histological analysis confirmed negative immunolabelling for ACTH, growth hormone, prolactin, and TSH. Despite subsequent growth, the tumour remained away from the optic chiasm until 2020, when its size increased from 4.9 cm in 2017 to 5.7 cm. While serial MRIs noted brainstem compression, there was no chiasmal involvement. By October 2024, the tumour had grown to 8.5 cm, significantly compressing the pontomedullary junction and optic chiasm, leading to visual field constriction, especially inferiorly and on the right. The Pituitary MDT ruled out radiotherapy (SRT and SRS) due to risks of tumour swelling and brainstem compression. Further surgery was postponed due to anaesthetic risks. Medical treatment with Cabergoline and Octreotide was recommended, with Temozolomide considered as a potential option based on its potential efficacy in improving clinical and radiological outcomes. Management requires expert team input, considering clinical findings, age, and comorbidities. Given the rarity of giant non-functioning pituitary adenomas, standardized protocols and research into predictive markers are essential to guide treatment decisions.