Pituitary apoplexy develops as a consequence of acute haemorrhage and/or infarction in a pre-existing pituitary adenoma. Typical symptoms include sudden onset headache, visual acuity/field defects, and ocular palsies. We report a male patient with a known pituitary macroadenoma who underwent a right-sided endoscopic nasal surgery. Preoperatively, thickening of sphenoid mucosa was seen in computed tomography and magnetic resonance imaging. The patient developed pituitary apoplexy postoperatively. The presented report indicates that in patients with a pituitary adenoma, nasal surgery - like any other kind of surgery - is a possible precipitating factor for pituitary apoplexy. Isolated thickening of sphenoid mucosa is associated with pituitary apoplexy. It may also precede an apoplectic event.