[A case of mycotic pseudoaneurysm of the external carotid artery following a peritonsillar abscess].

Mycotic pseudoaneurysm is a rare complication of deep neck infection. We report herein on a case of mycotic pseudoaneurysm of the external carotid artery following myelodysplastic syndrome and a peritonsillar abscess. The patient was a male in his 60s, who complained of a sore throat and swelling of the left side of his neck. CT scan of the neck showed a left peritonsillar abscess and a pseudoaneurysm of the left external carotid artery. To correspond to airway obstruction in the event that the pseudoaneurysm might rupture to the pharyngeal space, the patient was transferred to our hospital. Surgical management was not selected, since MRI taken just after the admission to our hospital demonstrated remission of the pseudoaneurysm by organization of the structure and decrease of the blood flow. An antibacterial drug and an antifungal drug, SBTPC and VRCZ, were administered to the patient, the inflammatory signs reduced and the size of the pseudoaneurysm gradually diminished without sequela. These findings strongly suggest the importance of controlling the initial neck infection by administration of appropriate antibacterial and/or antifungal drugs to avoid the expansion of the mycotic pseudoaneurysm. Furthermore, MRI was useful to assess the state of the lesion and to determine the way of management.