Revision 33 for 'Laryngocele'

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Laryngocoele

Laryngocoeles refer to dilatations of the laryngeal ventricular saccule located in paraglottic space of supraglottis.

On imaging, these lesions are generally characterized as well-defined, thin-walled, fluid or air-filled cystic lesions in the paraglottic space. The communication with the laryngeal ventricle is not always identified, and an extralaryngeal extension through the thyrohyoid membrane may or may not be present. 

Clinical presentation

When small, the lesions are usually asymptomatic and incidentally discovered when imaging the neck for other reasons. Symptoms vary accordingly to the size and extension of the lesion and may include: a sore throat, dysphagia, stridor, neck lump, and/or airway obstruction.

Pathology

Laryngocoeles are usually acquired rather than congenital. They are lined by pseudostratified, columnar, ciliated epithelium. Occasional areas of stratified squamous epithelium +/- submucosal serous and mucous glands may be present.

Classification

Three laryngocoele subtypes are described 2 :

  • internal (or simple): the dilated ventricular saccule is confined to the paralaryngeal space (~40%)
  • external: the saccule herniates through the thyrohyoid membrane, and the superficial portion is dilated (~25%)
  • mixed: with dilated internal and external components (~45%)
Risk factors

Raised intralaryngeal pressure secondary to:

  • excessive cough
  • playing woodwind/brass instruments
  • glass blowing
  • obstructing lesion, e.g. tumor

The finding of a laryngocoele should prompt a search for an underlying laryngeal carcinoma obstructing the orifice of the laryngeal ventricle 2. Secondary laryngocele is the term used when a tumor is the cause of a laryngocoele.

Radiographic features

Plain radiograph

Laryngocoeles are better appreciated on radiographs when having an air content. In those cases, an air pocket may be observed in the upper cervical paralaryngeal soft tissues.

CT

Typically seen as a well defined, air or fluid filled lesion related to the paraglottic space, which has continuity with the laryngeal ventricle. The extent will obviously depend on subtype.

Attenuation characteristics may vary depending on laryngocoele content (e.g. air, fluid, mucus).

MRI

Same morphological characteristics observed on CT, usually:

  • T1: low signal 
  • T2: high signal 
  • T1C+ (Gd): absent to minimal linear peripheral enhancement. When thick enhancing walls are present, consider pyolaryngocele

Complications

Differential diagnosis

Imaging differential considerations include:

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