Pharyngocele

A pharyngocele, also known as a lateral pharyngeal diverticulum, refers to a lateral pharyngeal wall herniation in the piriform recess or vallecula ^1,2.

Epidemiology

Pharyngoceles are rare and more often unilateral than bilateral ^2-4. It is commonly associated with occupational exposure to increased intra-pharyngeal pressure ^1,3 such as glass blowing or playing musical woodwind/brass instruments. It occurs more frequently in males than in females and usually arises during the fifth and sixth decades of life ^2,4,5.

Risk factors

Raised intrapharyngeal pressure secondary to ^1-7:

• playing woodwind or brass instruments
• glass blowing
• excessive cough

Clinical presentation

The majority of patients are asymptomatic ^4,5. The primary manifestation is dysphagia ^4-6 but other clinical features may include ^4,6:

• neck mass
• regurgitation
• odynophagia
• dysphonia
• otalgia
• cervical pain
• cough
• weight loss

Pathology

The two main factors involved in the pathogenesis of pharyngoceles are chronic elevation of intrapharyngeal pressure and pharyngeal wall weakness ^3-6.

Most documented cases in the medical literature have an association with the repeated elevation of intrapharyngeal pressure. Patients are typically glassblowers or musicians who play woodwind or brass instruments ^1-7.

Pharyngocoeles can arise from two areas of weakness on the lateral wall of the pharynx ^4,5.

1. between the superior and middle pharyngeal constrictor muscles
2. between the middle and inferior pharyngeal constrictor muscles ^4,5,7

^​Loss of muscle elasticity with aging and previous surgeries can contribute to the wall weakness ^2-5. A minority of patients have congenital causes thought to be due to branchial cleft anomalies ^2,3,7.

Radiographic features

Ultrasound

Pharyngocoeles may be seen on a transverse sonogram at the level of the ventricular folds ⁸ as a hyperechoic gas pocket which enlarges during a Valsalva maneuver ⁸. In pharyngoceles, gas communicates with piriform sinuses distinguishing it from laryngoceles which have gas communicating with laryngeal saccules ⁸. Identification of pharyngoceles on ultrasound can be difficult in the presence of thyroid calcification ^8,9.

Plain radiograph / fluoroscopy

Pharyngocoeles are best identified on the frontal barium swallow x-ray during a Valsalva maneuver ² before and after contrast administration. In bilateral pharyngoceles, a "bullfrog appearance" can be appreciated on frontal cervical x-rays ¹.

CT

CT and laryngoscopy are the diagnostic tools of choice ^4,5,7. Similar to radiographs, it is best appreciated during a Valsalva maneuver after ingestion of positive oral contrast medium ⁷. It is typically seen as a parapharyngeal gas sac that communicates with the base of the piriform sinus or the lateral side of the vallecula ⁵.

MRI

Morphologically is similar to findings on CT. Dynamic real-time and 3D MRI can allow for better visualization of the anatomy, specific location and characteristics of the lesion ^4,9.

Treatment and prognosis

Treatment is usually conservative involving healthy dietary habits, oral hygiene, avoiding activities that increase intrapharyngeal pressure and wearing a compressive neck wrap while doing those activities ^2,3,6,7. Surgical excision may be indicated in severely symptomatic patients ^2,3,5-7.

Differential diagnosis

• laryngocele
• apical lung herniation
• Zenker diverticulum
• jugular vein phlebectasia