Into the void: a giant aneurysm mimicking a macroprolactinoma

Excerpt

A previously well menopaused 51-year-old female presented with a 6-months history of headache, galactorrhea and peripheral vision loss. During investigation, mild hyperprolactinemia was found and a 1.7 cm × 1.4 cm × 1.3 cm intrasellar lesion, with heterogenous signal in T1W and hypointense in T2W, with suprasselar extension abutting the optic chiasm was detected on magnetic resonance imaging (MRI) (Fig. 1a, b). After an initial diagnosis of a macroprolactinoma, the patient was started on cabergoline therapy. Four months later, low levels of basal cortisol and FSH lead to the diagnosis of panhypopituitarism. Due to the emergence of fatigue, weight loss and nausea, a new MRI was performed revealing a suprasellar lesion, of approximately 2.5 cm × 1.9 cm × 1.6 cm, with a flow void phenomenon in T1W and T2W sequences (Fig. 1c, d). Therefore, because of the mass location and the flow void phenomenon, a giant circle of Willis aneurysm was suspected. A computed tomography (CT) angiogram revealed a saccular aneurysm of the internal carotid artery (IC), with sellar extension (Fig. 1e, f). Then an arteriography showed mirror aneurysms of the carotid siphon: a giant saccular aneurysm of 3 cm on the right and 0.4 cm on the left-side (Fig. 1g, h). Glucocorticoid coverage led to clinical improvement. An endovascular flow diverter was opted as the best treatment option.

…