222 Jallo et al. ommendation of close follow-up certainly should be heeded. Paul H. Chapman Boston, Massachusetts This is a report of two patients with a rare condition. This histological variant and its tendency to recur have been described previously, although mainly in the pathology literature. On the basis of early recurrence in both of patients, the authors recommend adjuvant therapy with radiation and/or chemotherapy after reoperation for recurrence and frequent surveillance scans. The follow-up is relatively short, however, and it is unclear how effective this strategy will be. In the meantime, it would seem rational to recommend adjuvant radiation after subtotal resection in newly diagnosed patients. Robin P. Humphreys Toronto, Ontario, Canada Leslie N. Sutton Philadelphia, Pennsylvania Distal Anterior Choroidal Artery Aneurysm in a Patient with Moyamoya Disease: Case Report Jung-Kil Lee, M.D., Je-Hyuk Lee, M.D., Soo-Han Kim, M.D., Min-Cheol Lee, M.D. Departments of Neurosurgery (J-KL, J-HL, S-HK) and Anatomic Pathology (M-CL), Chonnam National University Hospital and Medical School, Kwangju, South Korea OBJECTIVE AND IMPORTANCE: Distal anterior choroidal artery (AChA) aneurysms in moyamoya disease are rare, with few surgically verified reported cases. CLINICAL PRESENTATION: We report a rare case of distal AChA aneurysm associated with moyamoya disease in a 48-year-old man who presented with vomiting and severe headache. Computed tomographic scans revealed an intracerebral hematoma in the right temporoparietal lobe and a diffuse intraventricular hemorrhage. INTERVENTION: The hematoma was removed via computed tomography-guided stereotactic aspiration and ventricular drainage. Cerebral angiography showed a saccular aneurysm located at the distal branch of the right AChA. By means of magnetic resonance imaging, a small signal void lesion was detected in the periventricular area lateral to the trigone of the right lateral ventricle. The aneurysm was accurately accessed via a parietal cortical incision by use of magnetic resonance imaging-guided stereotactic localization. The aneurysm was successfully resected after undergoing trapping of the parent artery, and when the patient was discharged, he had no evidence of neurological deficit. The aneurysm was histologically verified to be a true aneurysm. CONCLUSION: Direct surgery should be considered in cases of ruptured distal AChA aneurysms located in the periventricular or intraventricular regions. (Neurosurgery 48:222–225, 2001) Key words: Anterior choroidal artery, Moyamoya disease, Peripheral aneurysm, Stereotactic localization Neurosurgery, Vol. 48, No. 1, January 2001 I t is well known that moyamoya disease is commonly accompanied by intracranial aneurysm. To our knowledge, 15 distal anterior choroidal artery (AChA) aneurysms associated with moyamoya disease have previously been described in the literature (3, 6, 10, 13, 15, 17, 21–25). Direct surgical intervention for the treatment of a ruptured distal AChA aneurysm in patients with moyamoya disease has been attempted in only four cases (3, 13, 15). The patient we present here is the second report of a histologically verified true aneurysm located at the distal AChA in patients with moyamoya disease. CASE REPORT History A 48-year-old man who experienced a sudden onset of severe headache, vomiting, and a decreased level of consciousness was brought to the emergency room on May 27, 1999. The neurological examination performed at admission revealed somnolence with left hemiparesis. The patient’s blood pressure was 180/120 mm Hg. Results of analysis of laboratory data were unremarkable. A computed tomographic scan showed a large intracerebral hematoma in the right temporoparietal lobe and diffuse intraventricular hemorrhage Downloaded from https://academic.oup.com/neurosurgery/article-abstract/48/1/222/2748918 by EKU Libraries user on 24 January 2019 Meningioma in children does not always follow the rules. Although uncommon in this age group, this tumor may arise in unusual locations, not necessarily juxtaposed to a dural or ependymal base, and frequently it may demonstrate worrisome histological features. This article offers yet another nuance on the problem of meningioma in children. Clear cell meningioma offers an “aggressive variant” of meningioma that occurs “at a younger age, with tumors in the lumbar region,” and distressingly caters to “local recurrence observed in slightly less than half of all patients.” Histological examination reveals “a relative lack of intranuclear cytoplasmic invaginations, whorling growth, or psammomatous bodies.” The reader is left with the thought that he or she will probably never encounter a patient with this problem, but also with the question, What should be done if this problem occurs? Tumor surgery in the region of the cauda equina is now fairly standard, but aggressive and recurrent are two words that stand out in describing this tumor. Even if total excision is achieved, in the face of a 42% recurrence risk, is one obligated to advise adjunct radiation or chemotherapy for all patients? Distal Anterior Choroidal Aneurysm FIGURE 2. Right carotid angiograms (A, anteroposterior view; B, lateral view), demonstrating typical findings of moyamoya disease and a saccular aneurysm arising from the peripheral portion of the right AChA. FIGURE 3. Axial T2-weighted MRI scan revealing a small signal void lesion lateral to the trigone of the right lateral ventricle, which suggests an aneurysm. Operation On July 27, 1999, with the CosmanRoberts-Wells head frame, a right temporoparietal craniotomy was performed, including dissection through the previously made parietal corticotomy. The encephalomalacic cortex lateral to the trigone was slightly blue, suggesting previous hematoma. The surrounding cortex was carefully examined, but the aneurysm embedded by the brain parenchyma was difficult to identify. By use of MRI-guided stereotactic localization (Fig. 3), the aneurysm could be exposed, although we were unable to clip the aneurysm. The aneurysm was successfully resected after trapping the parent artery. Postoperative course The postoperative course was uneventful, and the patient experienced no neurological deterioration. Histologically, the wall of the aneurysm consisted of a few intimal endothelial cells, a thickened media replaced totally by fiFIGURE 1. Computed tomographic scan showing massive intraventricular hemorrhage and intracerebral hematoma in the right temporoparietal lobe. brous tissue, and an adventitial layer. The internal elastic lamina was absent, although it was clearly observed in the parent artery (Fig. 4). These findings are consistent with a true aneurysm. There was no evidence of tumor, vascular malformation, or infection. Postoperative cerebral angiography indicated complete resolution of the aneurysm (Fig. 5). The patient was discharged in a neurologically intact condition on August 10, 1999, and was cleared to return to work. FIGURE 4. Photomicrographs of the surgically excised aneurysm. A, although the internal elastic lamina was clearly observed in the parent artery, it was absent in the intima of the aneurysmal dome (elastic fiber stain; original magnification ⴛ40). B, the media of smooth muscle was replaced with a thickened fibrous tissue (Masson trichrome stain; original magnification ⴛ20). DISCUSSION Cerebral aneurysm associated with moyamoya disease was first reported by Pool (18a) in 1967. Since then, more than 140 cases have been reported (1, 7). The incidence of intracranial aneurysms in patients with moyamoya disease ranges from 3 to 14% (1). The aneurysms are characteristically small, rarely exceeding 10 mm in diameter (1, 12). According to Kawaguchi et al. (7), aneurysms occur around the circle of Willis, in the basal ganglia (moyamoya vessels), and in collateral vessels (AChA or posterior choroidal artery), the distribution of which is 3:1:1, respectively. The overall outcome of the aneurysms associated with moyamoya disease is not good when considered with regard to aneurysms alone. Nevertheless, aneurysms Neurosurgery, Vol. 48, No. 1, January 2001 FIGURE 5. Postoperative angiogram demonstrating resolution of the aneurysm. in the collateral vessels or in the basal ganglia have less favorable outcomes than do those around the circle of Willis (7). Peripheral artery aneurysms are infrequent. In particular, distal AChA aneurysms are very rare; only 23 cases have been reported (16, 18, 26). Among them, 16 cases of AChA, including this one, were associated with moyamoya disease and are summarized in Table 1. Spontaneous Downloaded from https://academic.oup.com/neurosurgery/article-abstract/48/1/222/2748918 by EKU Libraries user on 24 January 2019 without subarachnoid hemorrhage (Fig. 1). The right M1 and both A1 segments could not be visualized via magnetic resonance imaging (MRI) angiography, a finding that suggested moyamoya disease. The hematoma was removed via ventricular drainage and computed tomography-guided stereotactic aspiration with urokinase irrigation. The patient gradually recovered, and motor weakness subsided, returning the patient to near normal. A cerebral angiogram obtained on July 15, 1999, demonstrated bilateral occlusion of the internal carotid artery at its terminal, abnormal moyamoya vessels, and a 6-mm saccular aneurysm in the peripheral portion of the right AChA (Fig. 2). A second MRI scan revealed a small signal void lesion in the periventricular area lateral to the trigone of the right lateral ventricle (Fig. 3). 223 224 Lee et al. TABLE 1. Reported Cases of Distal Anterior Choroidal Artery Aneurysms in Patients with Moyamoya Diseasea Location of Aneurysm Symptoms and Computed Tomographic Findings Age (yr)/Sex Takeyama et al., 1976 (22) Tanaka et al., 1978 (23) Takahashi, 1980 (21) Yamada et al., 1981 (25) 43/M Left trigone SAH Conservative No deficit 57/F Right TH IVH Conservative Died 59/M 42/F Left choroidal fissure SAH Right ICH Furuse et al., 1982 (3) 54/F 67/M Right Right TL ICH ICH with IVH Kasamo et al., 1984 (6) 55/F Right TH SAH (another aneurysm) Konishi et al., 1985 (10) 18/F Right ICH with IVH Nakai et al., 1992 (15) 13/M 34/F 57/F 43/M 57/M 50/F 42/M IVH IVH IVH SAH ICH with IVH ICH with IVH ICH Present case 48/M Right Right Right Left trigone Right trigone Right trigone Lateral to trigone, right Lateral to trigone, right Onda et al., 1988 (17) Morii et al., 1988 (13) a ICH with IVH Treatment Excision Clipping (ruptured aneurysm) Conservative Conservative Conservative Conservative Conservative Excision Excision Trapping and excision Trapping and excision Histology Outcome False aneurysm Homonymous hemianopsia Died No deficit Died Died False aneurysm False aneurysm True aneurysm No deficit True aneurysm No deficit SAH, subarachnoid hemorrhage; TH, temporal horn; IVH, intraventricular hemorrhage; ICH, intracerebral hematoma; TL, temporal lobe. regression or disappearance of peripheral aneurysms associated with moyamoya disease, especially in the basal ganglia or on the collateral vessels, are sometimes observed at follow-up angiography (7). In general, most peripheral aneurysms are considered to be false aneurysms (4). Although a few peripheral aneurysms have been confirmed histologically, only one recorded case in a patient with moyamoya disease was histologically verified as a true aneurysm (15). The histological examination of the resected aneurysm in the case we present here revealed it to be a true aneurysm: the aneurysmal wall consisted of endothelial and adventitial layers with fibrous tissue. The clinical findings of peripheral artery aneurysms seem to vary, depending on the location of the aneurysm; the characteristics of distal AChA aneurysms are as follows: they are usually located in the periventricular (subependymal) or intraventricular (plexal) regions rather than in the subarachnoid (cisternal) space; and aneurysmal rupture results in intraventricular hemorrhage with or without intracerebral hematoma (1, 9, 16). In the patient we treated, the aneurysm was located lateral to the trigone of the right lateral ventricle in the subependymal layer, resulting in intraventricular hemorrhage with intracerebral hematoma. Distal aneurysms may be difficult to localize because they are usually hidden from the cortical surface. Even though hemorrhage has occurred, detection of the aneurysm on the edge of the clot may be difficult. Accurate localization of small, deep lesions is possible via stereotactic techniques. Stereotactic localization in aneurysm surgery is not a new idea. Computed tomography-, MRI-, or angiographyguided stereotactic localization has sometimes been used in treating peripherally located aneurysms (2, 5, 8, 11, 14, 20). A probe placed proximal to the aneurysm allowed a direct approach and identification of the aneurysm with minimal brain manipulation. Therefore, the stereotactic technique used in the present case permitted a small cortical incision, minimal dissection, and accurate localization of the aneurysm. Several vital branches are derived from the cisternal segment, which is proximal to the plexal point. However, the plexal segment mainly feeds the choroid plexus, which extends from the temporal horn to the atrium and usually anastomoses with the posterior choroidal artery (16, 19). Neurosurgery, Vol. 48, No. 1, January 2001 Therefore, to prevent rebleeding, direct surgery should be considered in the case of ruptured distal AChA aneurysms located in the periventricular or intraventricular regions. With the help of stereotactic localization, they can be safely resected without any neurological damage. Received, May 30, 2000. Accepted, August 8, 2000. Reprint requests: Jung-Kil Lee, M.D., Department of Neurosurgery, Chonnam National University Hospital, 8 Hak-dong, Dong-ku, Kwangju, 501-757, South Korea. Email: leejk@medikorea.net REFERENCES 1. Borota L, Marinkovic S, Bajic R, Kovacevic M: Intracranial aneurysms associated with moyamoya disease. Neurol Med Chir (Tokyo) 36: 860–864, 1996. 2. Cunha e Sa M, Sisti M, Solomon R: Stereotactic angiographic localization as an adjunct to surgery of cerebral mycotic aneurysms: Case report and review of the literature. Acta Neurochir (Wien) 139:625–628, 1997. 3. Furuse S, Matsumoto S, Tanaka Y, Ando S, Sawa H, Ishikawa S: Moyamoya disease associated with a false aneurysm: Case report and review of the literature [in Japanese]. No Shinkei Geka 10:1005–1012, 1982. Downloaded from https://academic.oup.com/neurosurgery/article-abstract/48/1/222/2748918 by EKU Libraries user on 24 January 2019 Series (Ref. No.) Distal Anterior Choroidal Aneurysm Neurosurgery, Vol. 48, No. 1, January 2001 early treatment when contemporary frameless navigation techniques are used; treatment can be very satisfactorily performed. It is extremely rare that such an aneurysm could be reconstructed in such a way as to save the parent vessel. H. Hunt Batjer Chicago, Illinois The authors report a case of ruptured distal anterior choroidal artery aneurysm associated with moyamoya disease. This case represents the difficult problem of a ruptured saccular aneurysm located at the distal branch of the right anterior choroidal artery. This lesion is rare, but it sometimes occurs, and surgical intervention is extremely difficult (1, 2). In the rare situation the authors describe, the aneurysm was successfully resected after trapping of the parent artery by use of magnetic resonance imaging-guided stereotactic technique without any resultant neurological deficit. Kil Soo Choi Seoul, South Korea 1. Kawaguchi S, Sakaki T, Morimoto T, Kakizaki T, Kamada K: Characteristics of intracranial aneurysms associated with moyamoya disease: A review of 111 cases. Acta Neurochir (Wien) 138:1287–1294, 1996. 2. Nakai H, Yamamoto K, Sako K, Tanikawa R, Kunimoto M, Hashimoto M, Tomabechi M, Ohgami S, Yonemasu Y, Muraoka S: A ruptured aneurysm at the peripheral collateral circulation of the anterior choroidal artery in a patient with moyamoya disease: A case report [in Japanese]. No Shinkei Geka 20:985–990, 1992. The authors report a case of moyamoya disease associated with a ruptured distal anterior choroidal artery aneurysm. The patient was successfully treated by aneurysmal trapping with the aid of magnetic resonance imaging-guided stereotactic localization. Although the formation of aneurysms in abnormally dilated moyamoya vessels is a well-known phenomenon, histological observation of such peripherally located aneurysms has been reported infrequently. In addition to the histological findings of the aneurysm, the authors suggest how to reach such peripherally located aneurysms during surgery. In addition, this article contains a thoughtful review of the literature. 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Pool JL, Wood EH, Maki Y: On the cases with little about distal aneurysms in terms of abnormal vascular network in the cerebral their natural history and their risk of early basal region in the United States, in Kudo T rebleeding, particularly in comparison to (ed): A Disease with Abnormal Intracranial Vasthose located around the circle of Willis. cular Networks: Spontaneous Occlusion of the CirNevertheless, it is prudent to push for cle of Willis. Tokyo, Igaku Shoin, 1967, pp 63–68. 225