DOI: 10.33962/roneuro-2023-016 Spontaneous complete resolution of a giant cavernous carotid aneurysm in the setting of ipsilateral ICA occlusion Sura H. Talib, Mayur Sharma, Vishan P. Ramanathan, Yara Alfawares, Muntadher H. Almufadhal, Mustafa Ismail, Samer S. Hoz Romanian Neurosurgery (2023) XXXVII (1): pp. 101-106 DOI: 10.33962/roneuro-2023-016 www.journals.lapub.co.uk/index.php/roneurosurgery Spontaneous complete resolution of a giant cavernous carotid aneurysm in the setting of ipsilateral ICA occlusion Sura H. Talib1, Mayur Sharma2, Vishan P. Ramanathan3, Yara Alfawares3, Muntadher H. Almufadhal4, Mustafa Ismail4, Samer S. Hoz5 1 College of Medicine, University of Al-Mustansiriyah, Baghdad, IRAQ 2 Department of Neurosurgery, University of Louisville, KY, USA 3 University of Cincinnati College of Medicine, Cincinnati, OH, USA 4 College of Medicine, University of Baghdad, Baghdad, IRAQ 5 Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA ABSTRACT Background. Cavernous carotid aneurysms (CCA) are rare aneurysms with a relatively benign natural history. The association between CCA aneurysm and ipsilateral Internal carotid artery (ICA) thrombosis or occlusion has not been described previously. The management of patients with these dual lesions is a challenging problem. Case description. In this report, we describe an 18-year-old man who presented with left abducent nerve palsy of 3 weeks duration, and imaging revealed left CCA with left ICA occlusion. The patient was managed conservatively with clinical and imaging follow-up. The patient recovered well with complete resolution of clinical symptoms and disappearance of left CCA. Conclusions. The association of giant CCA and ICA occlusion on the same side is a rare phenomenon with no current consensus on the appropriate follow-up and management strategy. In this report, we described the first case of spontaneous complete disappearance of a giant CCA in the setting of ipsilateral ICA occlusion with complete resolution of symptoms at nine months of follow-up. INTRODUCTION Cavernous carotid aneurysms (CCA) are rare with a relatively benign natural history and a lower risk of morbidity and mortality compared to size-matched equivalent aneurysms at other locations [6]. When CCAs are asymptomatic or have mild tolerable symptoms, then conservative treatment can be justified with long-term clinic-radiological follow-up. Other forms of presentations may require a multidisciplinary team of neuroendovascular and micro-neurosurgeons with catheter-based therapy as the treatment of choice [10]. Although partial thrombosis of intracranial aneurysms is reported in Keywords cavernous carotid aneurysm, internal carotid artery, spontaneous resolution Corresponding author: Samer S. Hoz Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA hozsamer2055@gmail.com Copyright and usage. This is an Open Access article, distributed under the terms of the Creative Commons Attribution Non–Commercial No Derivatives License (https://creativecommons .org/licenses/by-nc-nd/4.0/) which permits non- commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of the Romanian Society of Neurosurgery must be obtained for commercial re-use or in order to create a derivative work. ISSN online 2344-4959 © Romanian Society of Neurosurgery First published March 2023 by London Academic Publishing www.lapub.co.uk http://www.lapub.co.uk/ 102 Sura H. Talib, Mayur Sharma, Vishan P. Ramanathan et al. large and giant aneurysms, a complete thrombosis is a rare phenomenon [2]. An interesting association is reported between large CCA thrombosis and parent vessel occlusion with many suggested theories [2]. With extreme rarity, a decrease in the size of the thrombosed aneurysm represents a regression in the hemodynamic pressure and indicates a better prognosis [3]. Here we describe the first report on the spontaneous total disappearance of a giant CCA in the setting of ipsilateral internal carotid artery (ICA) occlusion with complete resolution of symptoms. CASE SCENARIO An 18-year-old male patient presented to us with left abducent nerve palsy and recurrent attacks of a severe headache of nonspecific localization and character. Apart from the palsy, the patient was neurologically intact and had no remarkable medical history. Brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) at presentation showed a giant (28mm x 24mm x 21mm) left cavernous ICA aneurysm with mass effect on the left temporal lobe with a striking shadow of the thrombosed aneurysm and absence of the left ICA proximal to the clinoidal segment on MRA (Figure 1 A-D). The patient couldn’t afford the catheter angiography at that time. We opted to treat him conservatively with regular clinico-radiological follow-up. A 3-month follow-up MRI showed a reduction in the size of the aneurysm, loss of flow void signal intensity, and his symptoms improved. At the 9-month follow-up, the patient was neurologically intact and did not experience headaches over the last three months. His brain MRI and MRA cerebral revealed a complete resolution of the cavernous aneurysm, no mass effect on the temporal lobe with the disappearance of the aneurysmal shadow, and the absence of the left ICA on MRA (Figure 1 E-H). A 9-month follow-up digital subtraction angiography (DSA) showed complete occlusion of the left ICA just distal to its origin with sufficient collateral circulation from the right ICA. No aneurysmal filling was detected (Figure 2). The patient remained asymptomatic at the last follow-up. No further investigations were planned, and annual clinical assessment follow-up visits were scheduled. DISCUSSION CCAs are rare and constitute approximately 2-9% of all intracranial aneurysms [5]. They are predominantly asymptomatic, are discovered incidentally, and have a benign natural history with a low risk of rupture and complications. However, they may become symptomatic due to mass effects from an enlarged aneurysmal mass [6,14]. It is known that CCAs rarely cause rupture and subarachnoid hemorrhage (SAH) since the cavernous sinus is composed of thick double-dural membranes, which lay over the sphenoid body [16]. The optimal management strategy for CCA aneurysms remains controversial. Since CCAs are known to have a low propensity for a life-threatening sequela, conservative management with serial follow-up imaging seems to be a reasonable strategy. However, there are several compelling reasons to treat this entity, including a rupture with the formation of carotid-cavernous fistula, an increase in the size of the aneurysm on follow-up imaging, progressively worsening headache, and erosions of the sphenoid sinus. These signs and symptoms should be analyzed by a multidisciplinary team (neuro-endovascular and microsurgical) to choose the optimal treatment plan [1,6,14]. Aneurysms arising from the circle of Willis are likely to cause spontaneous SAH leading to a devastating neurological condition. On rare occasions, these aneurysms may undergo spontaneous thrombosis causing symptoms related to a local mass effect and or distal thromboembolism of the parent artery. Complete thrombosis of aneurysms occurs at a lower incidence in comparison to partial thrombosis (13- 20% vs. 60%); generally, it tends to occur in large (>15mm) and giant (>25mm) aneurysms [2]. The association of ipsilateral ICA occlusion with giant CCA is rare, with only 18 reported cases in the literature [1]. Theories addressing the coexistence of these two pathologies and their progression is a matter of contentious debate due to a limited number of reported cases and the variability in the characteristics, progression, and management strategies. One explanation is that the large thrombosed CCA tends to compress on the ICA against the anterior clinoid process and causes stenosis of the parent artery [8,15]. Other proposed theories include direct stretch and compression of the parent artery by the giant aneurysm and proximal propagation of an intramural thrombus [12]. On the other hand, thrombosis of the parent artery can be initially formed in association with giant 103 Spontaneous complete resolution of a giant cavernous carotid aneurysm in the setting of ipsilateral ICA occlusion CCA due to the presence of tough dural folds, bony structures along with the natural bend of the artery at this location, which facilitate parent artery deformity, blood flow stasis and eventually thrombosis. The resultant decreased flow into the aneurysm leads to intra-aneurysmal clot formation [2]. In our case, the treatment decision was challenging because the patient was young and had an acute presentation with abducent palsy of 3 weeks duration. However, the absence of ICA ipsilateral to the giant CCA led us to choose conservative management with regular follow-up imaging in the absence of a defined management strategy for these lesions. Then the patient did well with complete resolution of symptoms at nine months follow-up. Table 1. Characteristics and follow-up of patients with CCA aneurysm and ipsilateral ICA occlusion that were treated conservatively Authors Age- Year/ Sex Side Clinical presentation Imaging at presentation (MRI and DSA) Imaging at F/U (MRI and DSA) Clinical outcome Treatment Gautier, 1986. (14) 65/F left CN III, IV, VI palsies CCA: (23mm) Thrombosed ICA: occluded - Opthalmo paresis persisted The patient refused treatment Sato et al. 1990 (15) 49/M left Headache, CN III, VI, V1 palsies CCA: (3cm) partial thrombosed (MRI flow void) ICA: occluded - improved Kuroka wa et al. 2001. (10) 50/F Right Headache, CN III, VI, and V1 palsies. CCA: (25 mm) not thrombosed. ICA: Intact. CCA: has heterogenous thrombus on MRI but has no flow in DSA. ICA: Occlusion of petrous segment. (Time from diagnosis: 2 years). Only CN III palsy resolved. The patient refused treatment. Tsutsu mi al., et 2002 (11) 74/M right Cavernous sinus syndrome CCA: complete thrombosis (no flow on DSA) ICA: occluded - NA Dehdas hti et al. 2003 (4) 31/F Right Headache, CN III, and VI palsies. CCA: (30 mm) has heterogenous thrombus on MRI but has no flow in DSA. ICA: Intact. CCA: partial resolution (aneurysm decrease in size). ICA: Occlusion at the origin. (Time from diagnosis: 18 months). Neurologi cally intact. The patient refused treatment. Perrini al., et 2005(16 ) 47/M Right Headache, CN V1, V2 palsies. CCA: (28mm), complete thrombosis ICA: mild stenosis ICA: Occlusion at the origin. (Time from diagnosis: 6 weeks CN V palsy persist headache and diplopia resolved Treated conservativ ely with anti-platelet Vasconc ellos al., et 2009 (7) 47/F Right Headache, CN III, IV, V1, V2, VI palsies. - CCA: giant ICA: Occlusion (Time from diagnosis: 6 months) CN V palsy persist headache and diplopia resolved 104 Sura H. Talib, Mayur Sharma, Vishan P. Ramanathan et al. 44/F Left Headache, CN III, IV, VI, V 1, V2 palsies. CCA: giant ICA: Occlusion (Time from diagnosis: 6 months) CN VI palsy persist headache and diplopia resolved 65/F Right Headache, CN III, IV, VI, V1 palsies. CCA: giant, partial thrombosis ICA: partial occlusion ICA: Occlusion (Time from diagnosis: 5 years) CN palsies persist , headache and diplopia resolved 84/F Left Headache, CN III, IV, VI, V 1, V2 palsies. CCA: giant, partial thrombosis (heterogenous thrombus on MRI but has no flow in DSA). ICA: Occlusion at the origin. - CN III, VI palsies persist, CN IV, V partially improved, headache and diplopia resolved Sastri al. et 2013 (9) 65/F Left CN III, IV, VI, V 1, V2 palsies. CCA: giant, partial thrombosis. ICA: Occlusion at the origin. - Ophalmo paresis improved, CN V persist Treated conservativ ely on aspirin 55/F Left Seizure, decrease vision, CN III, IV, VI, V1, V2 palsies. CCA: (28mm) partial thrombosis ICA: Occlusion at the origin. - Ophalmo paresis improved, Decrease d Vision persist Treated conservativ ely on aspirin Das al.,et 2018(3) 45/M Left Headache, transient unconsciou sness CCA: (23mm) partial thrombosis ICA: Occlusion at the origin. - Neurologi cally intact Treated conservativ ely on aspirin Present cases 2022 18/M Left Headache, CN VI palsy. CCA: (28 mm) has heterogenous thrombus on MRI but has no flow in DSA. ICA: Occlusion. CCA: complete resolution (no aneurysm detected). ICA: Occlusion at the origin. (Time from diagnosis: 9 months). Neurologi cally intact. Treated conservativ ely on aspirin Shaded rows represent the patients with complete follow-up imaging. ICA - Internal carotid artery, DSA - Digital subtraction angiogram, MRI - Magnetic resonance imaging, CCA - Cavernous carotid aneurysm. In our case, a total of fourteen patients with concurrent ICA occlusion and CCAs have been treated conservatively, highlighting the natural history of this unusual association [2, 3, 4, 8, 16, 11 - 13, 15] (Table 1). Unfortunately, follow-up imaging was reported only in 7 patients, and, more specifically, concurrent follow-up MRI and DSA were available only in 3. Hence, only these 3 cases can be used to assess the actual progression of this disease with a high degree of certainty (Table 1-shaded rows) [3,8]. Lawton et al. proposed a new classification of thrombotic aneurysms based on anatomic relationships between the aneurysm, thrombus, and 105 Spontaneous complete resolution of a giant cavernous carotid aneurysm in the setting of ipsilateral ICA occlusion lumen [9]. They defined the completely thrombosed aneurysm as one with the classic signals of thrombus on the brain, Computed tomography (CT) scan/MRI, and the DSA showing no filling of the lumen [9]. Of the abovementioned three cases, two cases had a complete thrombosis at presentation, and they end with varying degrees of aneurysmal regression on follow-up [3]. The other patient had a non- thrombosed aneurysm at the initial imaging, which progressed to complete thrombosis at the 2-year follow-up [8]. The association between the CCA-ICA occlusion, degree of thrombosis, and outcome cannot be inferred due to the limited number of cases and limited follow-up. The timeline for the occurrence of the two pathologies (i.e., CCA and ICA occlusion) and which one is present at the presentation, and which one progress with the patient's symptoms is to be answered. For the fourteen cases that have been treated conservatively, eight patients had complete occlusion of the ICA at the presentation. The other six patients have either intact ICA at the initial investigation (2/14) or partially stenosed ICA at the presentation (2/14), with the initial occlusion status of the remaining two patients not mentioned. All the six cases of initially not occluded ICA end with complete occlusion but with variable duration and extension of occlusion. Those cases with delayed occlusion of ICA in the association of ipsilateral CCA (6/14) had a reported time for the occlusion to occur to be from 6 weeks to 5 years with a mean of 18.9 months. The location of the occlusion is at the origin of the ICA from the common carotid artery, with only one patient having a localized occlusion of the petrous and cavernous ICA [2, 3, 4, 8, 16, 11 -13, 15] (Table 1). Obviously, the limited number of cases produces this heterogenicity in the reported findings, and future studies are recommended to continue recruiting more patients and equally important that the patients should have a full radiological follow-up. This will have a profound impact on understanding this unique association, its related pathophysiology, and, most importantly, how to optimize treatment and prevention. Figure 1. Brain MRI and MRA At presentation (A-D) showed a giant Left cavernous ICA aneurysm with mass effect on the left temporal lobe (A, B) with a striking shadow of the thrombosed aneurysm and absence of the left ICA proximal to the clinoidal segment in MRA (C, D). 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