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Abstract
In patients with pituitary adenomas, incidental intracranial aneurysms have been documented. Previous studies have highlighted the importance of preoperative imaging in these patients. However, imaging may be limited and fail to show the presence of vascular abnormalities. In this report, we discuss a case of a man in his 30s presenting with a newly diagnosed pituitary adenoma. CT and MRI, on admission, showed a pituitary mass with extension into the right cavernous sinus. After a sudden neurological deterioration, emergent CT/CT angiography revealed pituitary apoplexy with subarachnoid extension without vascular abnormalities. Successful emergency transsphenoidal hypophysectomy was followed by digital subtraction angiography which revealed the presence of two right supraclinoid internal carotid artery aneurysms. With this case, we aim to highlight the need for further vascular imaging in patients with pituitary apoplexy and subarachnoid haemorrhage, as preoperative imaging may be negative for vascular abnormalities especially in the setting of cavernous sinus invasion.
- Neuroimaging
- Stroke
- Neurosurgery
- Otolaryngology / ENT
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Background
Pituitary adenomas, particularly somatotroph adenomas, have been linked to the presence of nearby or intratumoral aneurysms.1 Numerous case reports have discussed the importance of preoperative CT angiography (CTA), MR angiography (MRA) or digital subtraction angiography (DSA) in the management of patients undergoing pituitary tumour resection.2–6 Occult aneurysms not discovered on preoperative imaging increase the risk of complications stemming from possible aneurysm rupture. Subarachnoid haemorrhage (SAH) within the basal cisterns has been linked to both pituitary apoplexy and aneurysm rupture without definite differentiating bleeding patterns on imaging.7 Rare reports of concomitant pituitary apoplexy and aneurysmal rupture add further confusion.8 Thus, preoperative DSA could play a vital role in potentially confirming the presence or absence of aneurysms in case perioperative bleeding complications occur. In cases where no vascular abnormalities have been identified on MR or CT imaging, DSA performed prior to pituitary tumour resection can help rule out hidden aneurysms, as it is more sensitive to the detection of intracranial aneurysms less than 5 mm in size compared with CTA.9 Pursuing preoperative DSA is especially important when imaging shows that the tumour has invaded the cavernous sinus or when internal carotid artery (ICA) flow has been disrupted.3 Maintaining a high index of suspicion for accompanying aneurysms in the context of pituitary adenomas could not only help ensure safe tumour resection without intraoperative complications stemming from accidental aneurysm rupture but also ensure faster bleeding localisation in patients who deteriorate rapidly. Herein, we describe a case of SAH stemming from pituitary apoplexy requiring emergent operative intervention in the face of two aneurysms not seen on preoperative MRI or CTA. We hope to highlight the importance of maintaining a high level of suspicion for adjacent aneurysms in the setting of pituitary tumour resection even if preoperative CTA or MRI has not indicated the presence of aneurysms.
Case presentation
A previously healthy man in his 30s presented with a new onset non-remitting, severe bitemporal headache of 9-hour duration, nausea, diplopia and photophobia and phonophobia. He reported cocaine and heavy alcohol use on the evening prior to the presentation but denied a history of tobacco use. Blood pressure in the emergency department was normotensive at 127/80, however, the patient had a history of hypertension. He denied baseline headache history. He reported a 1-year history of peripheral vision loss, decreased libido and cold intolerance. Unfortunately, these symptoms were never investigated within an outpatient setting with any tests. Neurological examination was unremarkable with the exception of bitemporal hemianopsia. Endocrine labs drawn on admission, with their respective results, were as follows: FSH (Follicle Stimulating Hormone), <0.4 (Ref range: 1.4–18.1) MIU mL; TSH (Thyroid Stimulating Hormone), 2.59 (RR: 0.55–4.78) MCU; Prolactin, 1.9 (RR: 2.1–17.7) ng/mL; LH (Luteneizing Hormone), <0.4 (RR: 1.5–9.3) MIU mL; GH (Growth Hormone), 0.52 (RR: 0.05–3) ng/mL; ACTH (Adrenocorticotropic Hormone), 10.9 (RR: 7.2–63.3) pg/mL; Cortisol, 53 (RR: 5.2–22.5) mcg/dL; Insulin-like GF (Growth Factor), 196 (83–240) ng/mL and Free T4, 0.57 (RR: 0.89–1.76) ng/dL. A non-contrast head CT on admission revealed a 4.3×3.4×2.6 cm sellar mass favoured to be a benign pituitary neoplasm (figure 1A). An MRI of the brain with and without gadolinium contrast demonstrated central necrosis with a small amount of intratumoral haemorrhage, and tumour extension laterally into the right cavernous sinus with suspected encasement of the right cavernous ICA, suggesting Knosp grade 4 cavernous sinus invasion (figure 1B). Lateral displacement of the bilateral cavernous and supraclinoid ICAs was appreciated without loss of flow voids, and no concerning vascular malformations or aneurysms were noted. Fifteen hours after the headache onset, the patient decompensated acutely in the emergency room and was noted to have altered mental status, dysconjugate gaze and seizure-like activity.
Admission imaging. (A) Axial non-contrast head CT indicating size of the pituitary mass. (B) Axial T1-weighted MRI demonstrating involvement of the cavernous sinus. (C) Coronal T1-weighted MRI showing height of tumour in addition to invasion of the cavernous sinus.
Investigations
An emergent non-contrast head CT showed new haemorrhage around the sellar mass and significant SAH involving bilateral basal cisterns and sulci with intraventricular extension into the left lateral ventricle (figure 2A), mild hydrocephalus, and enlargement of the pituitary mass up to 5.3 cm in size in the craniocaudal dimension (figure 2B). CTA head once again showed no evidence of an aneurysm or vascular malformation. A significant mass effect on the bilateral supraclinoid internal carotid arteries was noted.
Imaging performed after acute deterioration. (A) Axial non-contrast head CT showing diffuse subarachnoid haemorrhage throughout basal cisterns and sulci. (B) CTA head demonstrating up to 1 cm enlargement in pituitary mass compared with admission imaging. CTA, CT angiography.
Differential diagnosis
The clinical picture of acute neurological decline with a new onset extensive SAH in the basal cisterns and sulci can be attributed to both pituitary apoplexy and aneurysmal SAH. The history of preceding cocaine use predisposes to both cocaine-induced pituitary apoplexy and intracranial aneurysm rupture. The lack of vascular abnormalities on CTA and MRI decreased the likelihood of aneurysmal aetiology of the SAH. Given the abrupt enlargement of the pituitary gland on short-interval follow-up imaging, pituitary apoplexy was suspected. Although a rare complication of pituitary adenomas, pituitary apoplexy has been known to present with SAH on imaging.10 11 Given the proximity of the pituitary gland to the basal cisterns, a compromise of the tumour capsule in the setting of pituitary apoplexy can lead to haemorrhage into the subarachnoid space—MRI can at times provide visualisation of these defects. The possibility of intratumoral aneurysm rupture leading to pituitary apoplexy was also on the differential, although considered unlikely.12
Treatment
Based on the patient’s acute neurological decline, hopes of preserving vision and imaging being negative for any vascular abnormalities, an external ventricular drain was placed at the bedside and the patient was immediately taken to the operating room for emergent transsphenoidal hypophysectomy with assistance from otolaryngology. Sellar tumour herniation was noted on exposure which extended from the lateral aspects of the sphenoid sinus up to the level of the skull base superiorly. All visible tumour was resected without complications. During the resection, a constant moderate bleeding was encountered consistent with venous cavernous sinus source. Good hemostasis was achieved at the end of the case. The sella was left decompressed without graft reconstruction, allowing for decompression and extracranial drainage of any recurrent haemorrhage. A 100 mg hydrocortisone was started three times a day postoperatively. Pathology confirmed the pituitary mass to be a gonadotroph adenoma, staining positive for luteinising hormone. The patient was then taken to the interventional angiography suite from the operating room. DSA revealed two right supraclinoid ICA aneurysms, including a saccular aneurysm measuring 2.5×1.8 mm in the region of the right posterior communicating artery and a posteriorly located 1.3 mm blister aneurysm in the region of the superior hypophyseal artery inferior to the saccular aneurysm (figure 3A). Both aneurysms were successfully embolised with flow diversion using a 3.5×12 mm pipeline stent (figure 3B). A contralateral view of pertinent cerebral vasculature from figure 3 can be seen in figure 4 for ease of comparison.
DSA demonstrating two right supraclinoid ICA aneurysms. (A) Anterior-Posterior (AP) and lateral views pre-treatment. (B) AP and lateral views post-embolisation. DSA, digital subtraction angiography; ICA, internal carotid artery.
CTA sections highlighting vascular structures contralateral to aneurysm location for comparison purposes. (A) Sagittal view. (B) CTA axial at approximate level of superior hypophyseal artery. (C) CTA axial at level of Pcom. CTA, CT angiography.
Outcome and follow-up
Postoperative imaging showed remnant sellar surgical bed hematoma without active bleeding. The patient’s hospital course was complicated by development of vasospasm on postoperative day 8 which eventually required intraarterial nicardipine therapy. He was closely followed by endocrinology for management of panhypopituitarism leading to significant hypotension and suspected diabetes insipidus. At the time of writing this case report, ophthalmological examination has suggested minimal preservation of any vision in addition to bilateral oculomotor nerve paresis. Unfortunately, the patient remains dependent on family for all activities of daily living, with a stark decline in overall mentation.
Discussion
The association of pituitary adenomas and adjacent aneurysms, whether asymptomatic or not, is well-documented in the literature.1 13 However, there is debate as to the correlation between these two pathologies occurring simultaneously in addition to questions surrounding the potential mechanism of adjacent aneurysm formation.14 Proposed mechanisms of aneurysm formation associated with pituitary adenomas have included local effects of pituitary hormones, mechanical tumour effects on local vasculature and even direct vessel invasion by the tumour.1 15 In fact, patients with pituitary adenomas who have tumour invasion into the cavernous sinus are at significant risk for the development of intracranial aneurysms.13 Also, it is well known that the use of cocaine can lead to vascular compromise, which may have been a contributing factor for the development of aneurysms in our patient.16 Regardless, maintaining a high index of suspicion is important in the management of pituitary adenomas as cases of transsphenoidal pituitary resections being complicated by aneurysmal rupture and severe haemorrhage have been published.17 18
Preoperative imaging of pituitary adenomas plays a major role in defining tumour morphology and location, but also regional vascular anatomy—including the presence of potential aneurysms. Although CTA, MRA and DSA have all been used to assess aneurysms, DSA is regarded as the gold standard. Previous studies investigating the diagnostic value of CTA and MRA using DSA as a reference standard have found an overall aneurysm detection sensitivity of 93.3%–97.2% and specificity of 87.8%–100% for CTA and 87%–95% and 92% for MRA, respectively.19 20 DSA has also been found to be better at detecting smaller aneurysms. According to one meta-analysis, CTA sensitivity decreased markedly from 96% to 61% when attempting to detect aneurysms less than 3 mm in size.21 A similar limitation was found for MRA, where sensitivity decreased from 94% to 38% while trying to detect the same-sized aneurysms.21 Additionally, CTA has been reported to miss aneurysms at the skull base, highlighting another important reason for choosing DSA for preoperative decision making.19 While DSA is more sensitive than the other imaging modalities, it also comes with additional risks and limitations, including cost, expertise required for operation, invasiveness, increased radiation exposure and potential toxicities of the contrast.20 22–24 Thus, the decision for DSA requires consideration of multiple factors, including the health of the patient and suspicion of occult aneurysms. Prior literature has mentioned the presence of flow-voids on T1-weighted and T2-weighted MRI sequences to help locate potential nearby aneurysms, although Olsen et al have discussed the notion that not all aneurysms will demonstrate flow—possibly the case in our patient as well.25 26 Zhu et al reported an incidence of pituitary apoplexy in the context of a radiographically occult aneurysm and attributed this finding to the fact that pituitary enlargement from pituitary apoplexy led to significant ICA occlusion, thus hindering aneurysm observation until recanalisation was achieved.27 Of note, our patient did not present with pituitary apoplexy at admission; however, slight compression of the ICA noted on imaging could have diminished aneurysmal blood flow—limiting observation preoperatively. Intraoperative injury to the supraclinoid ICAs must also be considered as a potential culprit in aneurysm formation; however, we felt this was less likely based on good intraoperative visualisation. Cases like this help demonstrate the importance of postoperative vascular imaging in which occult aneurysms, operative vascular injury or vasospasm can be discovered.28 29 In conclusion, we report here another case of local aneurysm formation being potentially associated with a pituitary adenoma invading the cavernous sinus. Although initial diagnostic imaging may not always be able to picture these small aneurysms, understanding that they might still be present is of tremendous importance for two main reasons. First, as both pituitary apoplexy and ruptured aneurysms could present with subarachnoid bleeding patterns, knowing the origin of the bleed could potentially save valuable time in determining the most appropriate intervention. Second, understanding the potential risk of aneurysm presence during transsphenoidal pituitary resection can help mitigate intraoperative risks. Therefore, preoperative DSA may be beneficial in ruling out coexistent aneurysms in patients with otherwise non-concerning MR or CT imaging, informing the surgical team of local vascular abnormalities. Postoperative DSA could also be instrumental for similar reasons, especially in patients with tumour features that could predispose to local aneurysm formation.
Learning points
Given the potentially increased incidence of aneurysms associated with pituitary adenomas, surgical tumour resection should be cautiously performed to avoid operative complications.
Aneurysms associated with pituitary adenomas may not always be visible on preoperative imaging, even with dedicated imaging sequences.
Pituitary apoplexy can present with subarachnoid bleeding patterns akin to aneurysm rupture which might also be simultaneously present with pituitary adenomas.
A high level of suspicion should be maintained for the presence of aneurysms with associated pituitary adenomas, even with negative imaging, if tumour invasion of the cavernous sinus is seen.
Aneurysm-negative MRI or CT angiography imaging in the context of pituitary adenomas should lower the threshold for pursuing digital subtraction angiography, especially in the context of preoperative planning.
Ethics statements
Patient consent for publication
References
Footnotes
Contributors AC contributed to manuscript drafting, literature review and figure generation. NJB contributed to manuscript drafting and literature review. PV and BCL contributed to finalisation of manuscript and participated in patient’s care.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.