【双语病例】左侧异常颈内动脉合并永存镫骨动脉1例

19 6月
History: A 10-year-old boy presents with left-sided predominantly conductive hearing loss. No pain or tinnitus was elicited on review of symptoms. On otoscopy, patient has a purple retrotympanic mass with decreased tympanic mobility. Patient is othewise healthy and has no family history of neoplasm or hearing loss.(男性、10岁、主要表现为左侧传导性听力丧失。无疼痛或耳鸣。耳镜检查示鼓膜后面紫色肿块,伴鼓膜流动下降。病人健康的,没有肿瘤或耳聋家族史。)

【病例】左侧异常颈内动脉合并永存镫骨动脉1例

Q1——The foramen ovale (卵圆孔)is abnormal on the left.
A True
B False
Q2——The finding suggests absence of the middle meningeal artery (脑膜中动脉)on the left.
A True
B False
Additional CT images

【病例】左侧异常颈内动脉合并永存镫骨动脉1例

【病例】左侧异常颈内动脉合并永存镫骨动脉1例

Q3——What is implied by the appearance of the left internal carotid artery? (左颈内动脉)
A Abnormal course arises from the cervical internal carotid artery.
B Abnormal course arises from the external carotid artery branches.
C There is dehisence of an otherwise normal vessel.
D There will be retrograde flow (逆流)in the horizontal petrous segment.(水平岩段)
Q4——What other finding is present?
A Persistent trigeminal artery 永存三叉动脉
B Persistent otic artery 永存耳动脉
C Middle-ear hemangioma 中耳血管瘤
D Persistent stapedial artery 永存镫骨动脉
Q5——The differential diagnosis for a pulsatile retrotympanic mass includes all of the following, EXCEPT?
A Facial nerve hemangioma 面神经血管瘤
B Aberrant internal carotid artery 异常颈内动脉
C Dehiscent jugular bulb 开裂颈静脉球
D Glomus tympanicum 鼓室球瘤
答案1—5:B B B D A

Findings and diagnosis

 

 

 

Findings
The CT images demonstrate distinct anomalies that have been described as often occurring together, although both are relatively rare. First, there is an elongated horizontal petrous carotid canal and absence of the vertical petrous segment. The carotid artery course is through the middle ear as it enters from below at an enlarged tympanic canal. There is no bony covering to the intratympanic segment, and, in this case, the vessel abuts the tympanic membrane and the ossicular chain. Laterally, the artery has a stenotic appearance, typical for this entity.

Second, there is absence of the left foramen spinosum through which the middle meningeal artery enters the extradural space intracranial as it arises from the mandibular branch of the maxillary artery. Absence or hypoplasia of the foramen spinosum is a direct association with the associated second diagnosis. Further evaluation of the CT images reveals an apparent soft-tissue prominence, asymmetric from the right side, along the expected course of the tympanic facial nerve. Infrequently, there may be subtle erosion of the cochlear promontory, which may contribute to sensineural hearing loss.

CT图像显示明显的异常,被发现经常同时发生的,虽然都是比较少见的。首先,水平岩段颈动脉管细长而垂直岩段缺失。颈动脉的过程是通过中耳从下面进入扩大的鼓室管,鼓室段没有骨覆盖,并且在这种情况下,血管紧靠鼓膜和听骨链。横向上,动脉有狭窄的外观,典型的实体。

其次,左棘孔的缺失,起源于上颌动脉的下颌支的脑膜中动脉经棘孔进入颅内硬膜外隙。棘孔缺如或发育不良直接关联着第二个诊断。CT图像的进一步研究揭示了一个明显的软组织隆起,与右侧不对称,沿鼓室段面神经的预期路径。偶尔,可能是耳蜗岬细微的侵蚀,这可能有助于感音神经性耳聋。

Differential diagnosis — retrotympanic mass
Vascular/pulsatile:血管性的/搏动的

  • Paraganglioma 副神经节瘤
  • Hemangioma 血管瘤
  • Dehiscent 开裂的 carotid artery 颈动脉
  • Aberrant carotid artery 异常颈动脉
  • Dehiscent jugular bulb  颈静脉球

Nonvascular:非血管性的

  • Cholesteatoma 胆脂瘤
  • Schwannoma 神经鞘瘤;
Diagnosis

Aberrant internal carotid artery (left) with associated persistent stapedial artery

左侧异常颈内动脉合并永存镫骨动脉

The stapedial artery is a vestige (遗迹) of which branchial arch (腮弓)?
A First
B Second
C Third
D Fourth
Discussion
Misdiagnosis of an aberrant internal carotid artery (ICA) prior to biopsy, myringotomy, or other surgery can have disastrous and potentially life-threatening results. This is a relatively rare abnormality, with an incidence of less than 1%. There is agenesis of the first segment of the internal carotid artery with persistent compensatory enlargement of the inferior tympanic artery, which enters below through the inferior tympanic canaliculus and the caroticotympanic artery, which is the vestigial remnant of the hyoid artery arising from the ICA.

With an incidence of less than 0.5%, persistent stapedial arteries are less common than aberrant carotid arteries. Similarly, failure to identify this anomaly can result in dangerous hemorrhage into the middle ear.

The embryologic development of the branchial system produces six paired arches and corresponding arteries. The primitive second arch gives rise to the hyoid artery, which gives rise to the stapedial artery near its origin from the internal carotid artery.

When a stapedial artery persists in postnatal life, the middle meningeal artery arises from it. The foramen spinosum is absent. A persistent stapedial artery arises from the petrous ICA, entering the hypotympanum in an osseous canal. It goes upward between the crura of the stapes. Then, it enters the facial canal and extends a short distance, together with the facial nerve. Behind the geniculate ganglion, it leaves the facial canal, then travels anteriorly and cephalad in the extradural space of the middle cranial fossa.

在活检,鼓膜切开术或其他手术之前,误诊异位颈内动脉,可能会产生灾难性的和潜在威胁生命的后果。异位颈内动脉是比较罕见的异常,发病率不到1%。颈内动脉第一段的缺如而致鼓室下动脉持续代偿性扩张,进入走形于下鼓室小管和颈鼓动脉下方;是起源颈内动脉的舌动脉遗迹。

永存镫骨动脉的发病率小于0.5%,较异位的颈动脉少见。类似地,如不能识别这种异常会导致危险的大出血进入中耳。

鳃系统的胚胎发育产生六组成对的腮弓和相应的动脉。原始第二腮弓引起舌骨动脉,导致附近的镫骨动脉起源于颈内动脉。

当出生后,镫骨动脉持续存在,脑膜中动脉来自它。棘孔缺失。起自颈内动脉岩段的永存镫骨动脉,通过骨管进入鼓室;向上于镫骨脚之间。然后,进入面神经管内,伴随面神经延续一小段距离,在膝状神经节后面,离开面神经管,然后穿行于中颅窝硬膜外隙的前部。

References
  1. Botma M, Kell RA, Bhattacharya J, Crowther JA. Aberrant internal carotid artery in the middle-ear space. J Laryngol Otol. 2000;114(10):784-787.
  2. Moreano EH, Paparella MM, Zelterman D, Goycolea MV. Prevalence of facial canal dehiscence and of persistent stapedial artery in the human inner ear: a report of 1000 temporal bones. Laryngoscope. 1994;104(3 Pt 1):309-320.
  3. Roll JD, Urban MA, Larson TC, Gailloud P, Jacob P, Harnsberger HR. Bilateral aberrant internal carotid arteries with bilateral persistent stapedial arteries and bilateral duplicated internal carotid arteries. AJNR Am J Neuroradiol. 2003;24(4):762-765.
  4. Thiers FA, Sakai O, Poe DS, Curtin HD. Persistent stapedial artery: CT findings. AJNR Am J Neuroradiol. 2000;21(8):1551-1554.
翻译仅作参考,不当之处,多多指出,交流学习。

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