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|LETTER TO EDITOR
|Year : 2015 | Volume
| Issue : 2 | Page : 270-272
Large thrombosed anterior communicating artery aneurysm in the sella turcica: A review of literature
Bing Zhao1, Yuanli Zhao2, Yong Cao2, Shuo Wang2
1 Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, National Clinical Research Center for Neurological Diseases (Center of Stroke, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease), Beijing, China; Department of Neurosurgery, Mayo Clinic, Rochester, United States
2 Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, National Clinical Research Center for Neurological Diseases (Center of Stroke, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease), Beijing, China
|Date of Web Publication||5-May-2015|
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, National Clinical Research Center for Neurological Diseases (Center of Stroke, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease), Beijing
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Zhao B, Zhao Y, Cao Y, Wang S. Large thrombosed anterior communicating artery aneurysm in the sella turcica: A review of literature. Neurol India 2015;63:270-2
Intrasellar aneurysms often mimic pituitary tumors and may potentially lead to a catastrophic bleeding if they are not appropriately recognized before surgery. Internal carotid artery (ICA) aneurysms are the most common intrasellar aneurysms  , while anterior communicating artery (ACoA) aneurysms may also be present. ,,, In this report, we present a case with a large thrombosed ACoA aneurysm in the sella turcica. We also present a review of four cases previously reported in literature and describe the characteristics symptoms, diagnosis and treatment of these aneurysms.
A 41-year-old woman complained of intermittent headache for 5 months and irregular menses for 3 months with no significant neurological deficits. She did not take any medication and these symptoms remained persistent. In March 2014, she underwent a cranial computed tomography (CT) scan which showed an intrasellar mass [Figure 1]a. The primary diagnosis was a pituitary tumor. For further evaluation of the lesion, she was referred to our hospital in April 2014. Her neurological examination was normal. The laboratory reports indicated that the basal levels of pituitary hormones were normal except for an elevated prolactin level of 35.6 ng/mL (normal range, 1.9-25 ng/mL). Her T1-weighted post-contrast MRI showed a partial enhancement of the lesion with the normal pituitary gland seen separately close to the sellar floor [Figure 1]a. A subsequent CT angiography (CTA); demonstrated an aneurysm of the ACoA. A three-dimensional digital subtraction angiography also confirmed a 17 × 16 × 14 mm ACoA aneurysm [Figure 1]b. The patient was evaluated by the cerebrovascular team. The two treatment options of aneurysmal clipping versus coiling were presented to the patient and her family, and they selected microsurgery.
|Figure 1: Preoperative sagittal T1 weighted post-contrast image showing an intrasellar mass (a). Three-dimensional digital subtraction angiography (b) showing an anterior communicating artery aneurysm|
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A left frontotemporal craniotomy was performed and the intraoperative findings confirmed the presence of a large ACoA aneurysm originating from the junction of the left A1 and A2 segments and extending into the sella turcica [Figure 2]a. The surgical procedure consisted of three major steps. First, after temporary occlusion of the left A1 segment, the aneurysmal neck was dissected and clipped. Second, the aneurysm dome was partially excised permitting removal of the intra-luminal thrombus with forceps and gentle suction. Finally, the aneurysm was completely dissected from bilateral optic nerves and the pituitary stalk, and its fundus resected to relieve the mass effect. The compressed pituitary stalk and the diaphragma sellae were identified after resecting the aneurysm [Figure 2]b. After surgery, the indocyanine green videoangiography showed complete obliteration of the aneurysm with a patent left A1 and A2 arteries. The patient recovered well without neurological deficits and the CTA confirmed the absence of any aneurysmal remnant [Figure 2]c. At a follow-up of 6 months, there was complete resolution of her symptoms and her menstrual periods resumed.
|Figure 2: Intraoperative images showing the aneurysm extending into the sella turcica (a); and, the compressed pituitary stalk after resection of the aneurysm (b); Postoperative CT angiography (c) showing the complete obliteration of the aneurysm|
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Intrasellar aneurysms often arise from the cavernous or clinoidal segment of ICA and extend into the sella turcica through the thin medial cavernous sinus wall.  However, ACoA aneurysms rarely occur in the sella turcica and are often associated with a long optic nerve and post fixed chiasm.  This anatomical feature allows ACoA aneurysms to reach the sella by displacing the diaphragm sellae downward. Our surgical findings confirmed that intrasellar ACoA aneurysms extended anteriorly and inferiorly into the sella compressing the pituitary gland and stalk.
To the best of our knowledge, four case reports of AcoA aneurysms in the sella turcica have been reported since 1980. ,,, Two of these aneurysms ruptured, while two others remained unruptured. The symptoms caused by these aneurysms included headache, low-back pain, nausea, vomiting, impaired vision, and temporal hemianopsia. In addition, intrasellar ACoA aneurysms rarely present with endocrinopathies including a hyperprolactinemia, gonadotropin deficiency and ACTH deficiency that are often associated with the ICA aneurysms.  However, this patient presented with irregular menses. Irregular menses may be due to an increase in the prolactin (PRL) level, possibly due to the pituitary stalk distortion caused by the aneurysm.
Among the four patients reported in previous studies, one patient presented with an acute subdural hematoma in the posterior fossa.  The other patients presented with an intrasellar mass that was seen on the CT or MRI scans. All these aneurysms were large thrombosed aneurysms and were more likely to result in an intrasellar mass effect. Therefore, these aneurysms may also be mistaken for a pituitary adenoma or other sellar-suprasellar tumors. In our patient, the T1-contrast MRI showed the partial enhancement of intrasellar lesion that gave it a marble-like appearance caused by the spreading of the luminal contrast in the patent areas partially surrounding the thrombosed areas within the aneurysm.  CTA or MR angiography should be performed to differentiate an intrasellar aneurysm from other intrasellar lesions especially if the patient does not present with the characteristic symptoms and imaging of sellar tumors.
Most intrasellar ICA aneurysms may be treated with surgical or endovascular procedures. In the four patients reported in literature, one patient successfully underwent endovascular management,  while in one other patient, an attempt to clip the aneurysm was unsuccessful.  Our patient presented with irregular menses with compression of pituitary stalk by the aneurysm and surgical resection of the large aneurysm relieved the mass effect bringing about improvement in the patient's condition. There was no difficulty encountered while dissecting the neck and dome of the aneurysm from bilateral optic nerves and the pituitary stalk.  In addition, temporary clipping of the proximal anterior cerebral artery, partially excising the aneurysmal sac, and removing the intraluminal thrombus helped in applying the clip to the neck of large thrombosed intrasellar aneurysm.
| » Acknowledgements|| |
This work was supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology (Grant 2013BAI09B03) and National Natural Science Foundation of China (Grant 81471210). We thank Dr Tarun Singh, for English language correction.
| » References|| |
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[Figure 1], [Figure 2]