venerdì 1 ottobre 2010

Tornwaldt cyst




Findings

There is no intracranial hemorrhage, calvarial fracture or transtentorial herniation. On the lower images of the brain, there is a cystic hypoattenuating lesion at the posterior wall of the nasopharynx measuring 1.4 x 1.2 cm.


Diagnosis: Tornwaldt cyst


A Tornwaldt cyst is a benign proteinaceous cyst that is located in the midline of the posterior nasopharynx, superficial to the superior constrictor muscle of the pharynx. It is surrounded by adenoid tissue and arises from notochordal remnants in the pharyngeal bursa (pouch of Luschka). They are seen in up to 4% of the population (equally in males and females) and are usually asymptomatic unless they become infected. If infected, they can cause a variety of symptoms including purulent drainage, sore throat, prevertebral muscle spasms, halitosis and Eustachian tube obstruction.

These fluid-filled cysts are usually discovered on imaging (both CT and MRI) as incidental findings. The cyst is well-circumscribed and located in the midline in the posterior nasopharynx (between the longus coli muscles). On CT, it is hypo-attenuating and appears cystic. It will almost invariably appear bright on T2-weighted images. The T1 signal will vary from CSF signal to very bright hyperintensity depending on the amount of protein, fat, hemorrhage and mucus within the cyst. A thin rim of peripheral enhancement may be seen with gadolinium administration. Nasopharyngoscopy, although not necessary for asymptomatic cases, can help supplement the diagnosis.

Treatment is not necessary in most cases. For the rare symptomatic cases treatment options include surgical excision, electrocoagulation or marsupialization.

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