With the recent advances in imaging technologies for preoperative detection, the incidence of concomitant PA with an unruptured IA has ranged from 2.3 to 8.3% in the last decade [5, 6]. Although it is possible for such patients to develop either apoplexy from PA or SAH from a ruptured IA, the simultaneous ictus of both pathologies is extremely rare. Yoshida et al. [4] recently described a patient who developed SAH from an anterior communicating artery aneurysm. Within a few days, the patient developed progressively declining vision, most likely due to the aneurysm embedding within the PA. The authors also reviewed four other publications of similar events. All of the cited case reports of SAH associated with pituitary apoplexy were due to ruptured aneurysms at the supraclinoid parts of the ICA [4]. A recent systematic review by Piper et al. [7] selected only case reports in which the ICA aneurysms had direct contact with the co-existing PAs. Most of them were unruptured aneurysms at the cavernous ICA. The review showed that only 2 of 21 patients with PA had aneurysm rupture that caused massive epistaxis, but none had SAH [7].
Our present case involved an exceedingly rare occurrence of a ruptured intratumoural ICA aneurysm that initially caused severe headache and visual decline from pituitary apoplexy. A patient with a similar condition was described by Suzuki et al. [2]. This patient also had a high serum prolactin level but had no SAH. Unlike our patient, whose treatment was delayed by the interhospital transfer process, the patient described by Suzuki et al. [2], underwent urgent transsphenoidal surgery for tumour resection. Short of a preoperative vascular imaging study, the surgeons unexpectedly came across massive bleeding during the procedure. After significant intraoperative haemorrhage, temporary tamponade finally achieved haemostasis, and subsequent cerebral angiography revealed a cavernous ICA aneurysm. Eventually, endovascular occlusion of the ICA was performed with a good outcome [2]. Krug et al. [3] reported another similar case involving a patient who had Crooke cell pituitary apoplexy with a simultaneous 3-mm intratumoural pseudoaneurysm of the ICA and normal ophthalmologic examination findings. This patient underwent uneventful partial tumour resection with intentional sparing of the vicinity of the pseudoaneurysm via the transsphenoidal route, and a flow-diverting stent was placed thereafter [3]. In retrospect, based on the two aforementioned case reports in which the patients survived, our patient could have been more ideally cared for by 1) undergoing CT angiography at the local hospital to save time before his transfer to our institute; 2) undergoing an endovascular procedure to assess the collateral circulation and determine if complete occlusion of the left ICA was necessary; and 3) after the aneurysm had been secured, undergoing transsphenoidal surgery or receiving a dopamine agonist as early as possible. A hybrid operating theatre could have also been helpful in this situation. However, with the delays of the time-consuming inter-hospital transfer and the repeated rupture of the aneurysm, the patient eventually died. Despite the high index of suspicion of a pseudoaneurysm on CT angiography, a pseudoaneurysm was not confirmed either by cerebral angiography or at autopsy.
Unlike a true aneurysm, which is bounded by all three layers of the arterial wall (tunica intima, tunica media, and tunica adventitia), a pseudoaneurysm, or false aneurysm, is an abnormal outpouching or dilation of an artery that is only bounded by the outermost layer of the arterial wall (tunica adventitia). Because of the poor support of the pseudoaneurysm wall, it is unstable and thus poses a higher risk of rupture than a true aneurysm of comparable size. Additionally, there is a risk of growth and rupture due to the pulsatile inflow and outflow of blood through the neck of the pseudoaneurysm. Although rare, death may occur if an intracranial pseudoaneurysm remains untreated [8]. The causative effect of a pseudoaneurysm on the development of pituitary apoplexy, or vice versa, is debatable. In the present case, the small area of blood medial to the left cavernous ICA on the first CT scan could have represented early haemorrhage from either the pseudoaneurysm or the apoplexy. However, in contrast to typical patients with apoplexy, our patient experienced multiple episodes of increasing severity within a very short time span; this is largely uncommon for apoplectic PA. What exactly triggered this catastrophic event remains unknown. In this case, the rapid expansion of apoplectic PA could have led to vascular injuries, potentially resulting in pseudoaneurysm formation. Atherosclerosis, as evidenced by imaging, may jointly promote pseudoaneurysm development. However, the true aetiology of the pseudoaneurysm in this case is unknown. As a result, we acknowledge that this case report has some limitations.
In conclusion, we have herein described the development of an intratumoural pseudoaneurysm of the cavernous ICA as a potential cause or result of pituitary apoplexy. The possibility of a complicated aneurysm should be considered in apoplectic patients with recurring episodes of severe headache with a crescendo pattern and a mass effect to the surrounding structures.
