Endocrine Abstracts

A 61 year old female, without significant medical history, presented to her optometrist in Feb 2018 with clouding of vision and left sided proptosis. Opthalmic examination showed vision 6/7.5 right and 6/9 left eye, 3 mm proptosis on the left and diplopia on upward and right lateral gaze. Brain MRI demonstrated 6.3×5.6×5.8 cm lesion centered in the clivus and pituitary fossa, expanding in all directions; the bulk of the lesion was in the left parasellar region, encasing a patent cavernous segment of the internal carotid artery and displacing the left arm of the circle of Willis superiorly; anteriorly it was insinuating through the left superior orbital fissure and optic canal, displacing and partially encasing the left optic nerve medially, with a small component protruding into the left orbital compartment and causing moderate proptosis; posteriorly it was plastered against the surface of the midbrain and pons, partially encasing the basilar artery. Anterior pituitary profile was unremarkable. Transsphenoidal biopsy in March 2018 was consistent with a pituitary adenoma, with negative hormone staining and focally increased Ki-67 (up to 6–7%). CT neck/chest/abdo/pelvis showed 2 tiny indeterminate lung nodules, which have been discussed with respiratory and likely benign, however repeat interval imaging is advised. Transsphenoidal substantial biopsy was performed in May 2018 and pathology confirmed previous findings with Ki-67 10%. Postoperative assessment thus far reveals unchanged vision and persistent left sided proptosis. Immediate management plans include external radiotherapy and careful follow up of the lung lesions. This is a very rare case of a pituitary tumour invading the orbit causing left sided proptosis. The most common tumours with orbital invasion are meningiomas; this finding is exceptionally rare with pituitary adenomas. The prognosis of pituitary tumours with orbital invasion is considered poor, depending significantly on histology, extent of invasion and tumour burden.