Pituitary apoplexy: an update on clinical and imaging features

Abstract

Pituitary apoplexy (PA) is a rare and potentially fatal clinical condition presenting acute headache, vomiting, visual impairment, ophthalmoplegia, altered mental state and possible panhypopituitarism. It mostly occurs in patients with haemorrhagic infarction of the pituitary gland due to a pre-existing macroadenoma. Although there are pathological and physiological conditions that may share similar imaging characteristics, both clinical and imaging features can guide the radiologist towards the correct diagnosis, especially using magnetic resonance imaging (MRI). In this review, we will describe the main clinical and epidemiological features of PA, illustrating CT and MRI findings and discussing the role of imaging in the differential diagnosis, prognosis and follow-up. Teaching points • Headache, ophtalmoplegia and visual impairment are frequent symptoms of pituitary apoplexy. • CT is often the first imaging tool in PA, showing areas of hyperdensity within the sellar region. • MRI could confirm haemorrhage within the pituitary gland and compression on the optic chiasm. • Frequent simulating conditions are aneurysms, Rathke cleft cysts, craniopharingioma and mucocele. • The role of imaging is still debated and needs more studies.

Fig. 1

CT appearance of pituitary apoplexy. Arrows on axial (a), coronal (b) and sagittal (c) reconstructions indicate an intrasellar lesion, dis-homogeneously hyperdense, due to the presence of haemorrhagic components. The utility of reformatted images in the evaluation of the intrasellar hyperdensity is evident

Fig. 2

MRI performed in a patient with acute headache, mydriasis and visual impairment shows acute/early subacute phase haemorrhagic infarction within a pituitary macroadenoma. The intrasellar mass appears slightly hyperintense on unenhanced T1WI (axial, a; coronal, b; sagittal, c) with areas of hypointense signal on T2WI (axial, d; coronal, e) because of the presence of deoxyhaemoglobin. Coronal T1 contrast-enanched images (f) show left cavernous sinus involvement, probably leading to visual symptoms

Fig. 3

Large pituitary macroadenoma with MRI signs of subacute haemorrhage. In this phase, haemorrhage appears hyperintense on both T1WI (b) and T2WI (a). In the T2WI (a, e), thickening of the sphenoid mucosa (arrow) is evident as well. This sign is highly specific for pituitary apoplexy. On contrast-enhanced MRI (c, d, f) the residual pituitary gland enhances (arrow in c compared to b). Note the optic pathway compression, more evident on T2WI

Fig. 4

The figure shows an oval-shaped, haemorrhagic lesion within a pituitary adenoma, homogeneously hyperintense on both T1- and T2-weighted images (WI) (a), with a hypointense rim on T2WI (b, white arrow). Contrast-enhanced T1WI (c) shows strong, homogeneous enhancement of the pituitary gland and stalk, both displaced by the tumour

Fig. 5

Aneurysm of the carotid siphon as shown on contrast-enhanced T1WI (a, arrows). Axial and coronal T2WI (b, c) show the presence of a hyperintense lesion with a peripheral hypointense rim. Contrast-enhanced MR angiography with 3D reconstruction (d) clearly shows the exact nature of the lesion

Fig. 6

Suprasellar RCC appears hyperintense on T1WI (a, b) without contrast enhancement (d). On coronal T2WI (c), an arrow indicates an intracystic hypointense nodule, a typical sign of RCC, related to proteinaceous concretion. MR angiography (e) can be useful to rule out the possibility of an aneurysm, but the cyst will appear mildly hyperintense on MIP reconstruction

Fig. 7

Pituitary apoplexy in a patient with pre-existing adenoma. Arrows on sagittal and coronal T2WI (a, b) as well as in coronal T1WI show an area of haemorrhage within the adenoma. Haemorrhagic components appear hyperintense on both T2WI and T1WI. In (d) sagittal contrast-enhanced T1WI showing peripheral enhancement. Despite the absence of chiasm compression and cavernous sinus involvement, this patient underwent surgical treatment with a transsphenoidal approach. Sagittal T1WI follow-up during surgery on intraoperative MRI (Brain Suite) (e) and late follow-up (3 months later, f) show good imaging results

Fig. 8

Series of coronal T1WI follow-up images in a patient with a history of pituitary apoplexy. The patient presented to us for observation in July 2008 with sudden headache (a). He underwent conservative treatment. Further MRI studies demonstrated progressive reduction of the haemorrhagic component over time (b, c). Because of a new sudden episode of headache, he underwent a new follow-up (d) that showed a new increase in the size of the T1WI hyperintensity, suggesting re-bleeding. Further follow-up showed a reduction of haemorrhage during the next 2 years