Infected ICA pseudoaneurysm

Case contributed by Craig Hacking


Right neck pain and swelling. Intravenous drug user.

Patient Data

Age: 20 years
Gender: Female

Normal three-vessel origin from the aortic arch.

A 9 mm saccular pseudoaneurysm arises from the right lateral aspect of the superior cervical segment of the right ICA, approximately 15 mm below the base of skull and the neck measures 6 mm. The right ICA demonstrates normal caliber and contrast opacification, both proximal and distal to the pseudoaneurysm. The remaining major arteries of the neck are normal. No further aneurysms.

Fluid attenuation material surrounds the right ICA pseudoaneurysm in the superior aspect of the right carotid space, without an enhancing wall (arterial phase study). Adjacent fat stranding and edema within the right parapharyngeal fat space. Mild positive mass effect within the right suprahyoid neck. Retropharyngeal phlegmon is also noted, extending inferiorly to the C5/C6 level. The right pyriform fossa is partially effaced. The right palatine tonsil is slightly hypoattenuating compared to the left tonsil. The right IJV is effaced. Mild asymmetric enlargement of the right submandibular gland.

Lymphadenopathy within the right neck, measuring up to 14 mm short axis (right level IIa). 

The lung apices are clear. No destructive osseous lesion.


  • Pseudoaneurysm arising from the right lateral aspect of the superior cervical segment of the right ICA.
  • Diffuse inflammatory changes within the right neck, with no walled-off collection. Edema and phlegmon surrounding the right ICA pseudoaneurysm in the superior carotid space without a discrete fluid collection.
  • US of the jugular veins is suggested if the exclusion of thrombosis is needed.

Case Discussion

The patient deteriorated with the phlegmon progressing to an abscess which required surgical drainage. Micro from the operative drainage specimen grew Streptococcus pyogenes.

The ICA pseudoaneurysm was treated with endovascular ICA sacrifice.

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