AJR ARRS Membership
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wong, K. T.
Right arrow Articles by Ahuja, A. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wong, K. T.
Right arrow Articles by Ahuja, A. T.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
DOI:10.2214/AJR.04.1332
AJR 2005; 185:1355-1357
© American Roentgen Ray Society

Case Report

Unusual Anterior Neck Mass Visible Only During Valsalva's Maneuver in a Child

Ka Tak Wong1, Dennis L. Y. Lee2, Monica S. M. Chan1, Raymond K. Y. Tsang2, Edmund H. Y. Yuen1 and Anil T. Ahuja1

1 Department of Diagnostic Radiology & Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing St., Shatin, Hong Kong, SAR.
2 Department of Surgery, Division of Otorhinolaryngology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR.

Received August 25, 2004; accepted after revision October 15, 2004.

 
Address correspondence to K. T. Wong (wongkatakjeffrey{at}hotmail.com).


Introduction
Top
 Introduction
Case Report
 Discussion
 References
 
A child with an anterior neck mass is a common clinical presentation. To the best of our knowledge, there are only a few conditions in which the neck mass is apparent or aggravated only during Valsalva's maneuver. We present an unusual case of a superior herniation of the normal mediastinal thymus into the lower anterior neck in a child during Valsalva's maneuver. The role of imaging in the diagnosis and common differential diagnoses are discussed.


Case Report
Top
 Introduction
 Case Report
Discussion
 References
 
An 8-year-old boy presented with a lower anterior midline neck mass that had been present for 4 years that appeared only during shouting or straining. He had no dysphagia, hoarseness of voice, or shortness of breath. Physical examination revealed a tense swelling in the midline position of the lower anterior neck that became apparent only during Valsalva's maneuver (Figs. 1A and 1B). The lower border of the mass was not palpable. The mass was not compressible and did not move when swallowing; tongue tug was negative. The overlying skin was intact with no discoloration or ulceration. No other neck mass or cervical lymphadenopathy was detected. Flexible laryngoscopy did not show any abnormalities in the larynx or hypopharynx. The preliminary differential diagnoses included laryngocele and jugular phlebectasia.



View larger version (109K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1A —8-year-old boy with anterior neck mass that appears only during Valsalva's maneuver. Clinical photographs show mass in lower anterior neck appears during Valsalva's maneuver (A) and disappears during normal breathing (B).

 


View larger version (114K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1B —8-year-old boy with anterior neck mass that appears only during Valsalva's maneuver. Clinical photographs show mass in lower anterior neck appears during Valsalva's maneuver (A) and disappears during normal breathing (B).

 
High-resolution sonography of the neck with the child performing Valsalva's maneuver showed a well-circumscribed hypoechoic mass with lobulated outlines, multiple small echogenic foci, and linear echogenic lines in the midline of the lower neck anterior to the cervical trachea (Fig. 1C). The mass descended back into the upper mediastinum after completion of Valsalva's maneuver.



View larger version (139K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1C —8-year-old boy with anterior neck mass that appears only during Valsalva's maneuver. Transverse gray-scale sonogram of lower anterior neck during Valsalva's maneuver shows well-defined hypoechoic mass (solid arrows) with lobulated margins and multiple echogenic foci and lines anterior to cervical trachea (arrowheads). Note its close relationship with trachea and right common carotid arteries (open arrow), which are neither compressed nor displaced.

 
Because the inferior portion of the mass could not be well delineated on sonography, MRI was performed; MRI showed a triangular-shaped suprasternal mass continuous inferiorly with the normal thymus in the anterior superior mediastinum (Fig. 1D). The neck mass had a signal intensity similar to that of the normal thymus. There was no compression on adjacent structures in the anterior mediastinum and lower anterior neck. The mass herniated superiorly into the lower neck with bulging contours during Valsalva's maneuver (Fig. 1E). No focal mass was detected within the thymus.



View larger version (100K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1D —8-year-old boy with anterior neck mass that appears only during Valsalva's maneuver. Midline sagittal T2-weighted MR image (TR/TE, 1,000/65; number of signals averaged, 2) during normal breathing shows suprasternal mass (solid arrow) continuous with normal thymus in anterior superior mediastinum (open arrow). Note its triangular configuration at its superior margin, identical signal intensity to thymus, and lack of mass effect on underlying large vessels.

 


View larger version (109K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1E —8-year-old boy with anterior neck mass that appears only during Valsalva's maneuver. Midline sagittal T2-weighted MR image (1,000/65; number of signals averaged, 2) obtained during Valsalva's maneuver shows there is superior herniation of thymus into lower anterior neck (arrow), causing focal bulging of contour in anterior neck.

 
The overall imaging appearances were of a normal thymus with unusual superior herniation into the lower neck during Valsalva's maneuver.


Discussion
Top
 Introduction
 Case Report
 Discussion
References
 
The thymus develops from the third pharyngeal pouch together with the inferior parathyroid glands at the fifth week of gestation. The developing encapsulated thymic primordia maintains its close relation with the parietal pericardium and descends with the pericardium during 7-8 weeks of gestation to assume its characteristic location in the superior anterior mediastinum anterior to the great vessels [1]. Mandell et al. [2] showed intermittent superior movement of the normal thymus from the superior mediastinum into the cervical region during periods of forced exhalation that caused posterior buckling of the cervicothoracic trachea in infants. However, the phenomenon is subclinical and does not cause any tracheal luminal compromise. This case is unusual because the child is older and the degree of superior herniation of the mediastinal thymus is dramatic, causing the clinical symptom of a palpable neck mass. The proposed mechanism postulated is that the connective tissue limiting the normal movement of the thymus is exceptionally loose, which causes the thymus to move into the neck during increased intrathoracic pressure produced by Valsalva's maneuver.

The diagnosis of superior herniation of normal thymus in the neck in this child was made radiologically by virtue of its shape, location, continuity with the normal mediastinal thymus, absence of compression on adjacent structures on MRI, and characteristic sonographic appearances. In children, normal thymic parenchyma has multiple echogenic foci and linear structures on high-resolution sonography [3, 4]. The appearance is presumably related to the presence of connective tissue septa or blood vessels within the septa [5].

The differential diagnosis of midline anterior neck mass in children includes thyroglossal duct cyst, dermoid-epidermoid cyst, cystic hygroma, thyroid mass, and ectopic thymic mass [6]. The fact that the mass in this child occurred only during Valsalva's maneuver virtually rules out all those possibilities.

Laryngocele and phlebectasia are the only two conditions that may produce similar clinical presentation and can be easily differentiated from one another on imaging. Laryngocele, an abnormal dilatation of laryngeal saccule, can occur in children but is more common in adult men in the fifth decade. CT is the preferred imaging technique for evaluating laryngocele, which appears as a gas-filled dilated laryngeal saccule extending to the paraglottic region (internal laryngocele). It may protrude through the thyrohyoid membrane to the lateral neck (external laryngocele) [7] and, at that time, be visualized even on sonography. Laryngocele may be filled with air, fluid, pus, or a combination [8].

Phlebectasia is dilatation of an isolated vein, and the internal jugular vein is the most commonly affected. It may present with cervical swelling that expands with increased intrathoracic pressure [9]. On rare occasions, the anterior jugular vein can be affected [10]. Clinically it would be located in a more lateral position (more commonly on the right), which could help to differentiate it from a laryngocele. Sonography supplemented by Doppler examination accurately identifies the dilated internal jugular vein on Valsalva's maneuver with venous blood flow [9, 10].

In summary, symptomatic superior herniation of the normal mediastinal thymus into the lower anterior neck during Valsalva's maneuver is a rare condition. High-resolution sonography and MRI confirm the diagnosis by showing its continuity with the normal mediastinal thymus and the typical sonographic echo pattern of normal thymic tissue. Otorhinolaryngologists and radiologists should be aware of this unusual clinical entity to prevent unnecessary biopsy or surgery.


References
Top
 Introduction
 Case Report
 Discussion
 References
 

  1. Moore KL, Persaud TVN. The pharyngeal apparatus. In: Moore KL, Persaud TVN, eds. The developing human: clinically oriented embryology, 7th ed. Philadelphia, PA: Saunders 2003:202 -240
  2. Mandell GA, Bellah RD, Boulden ME, et al. Cervical trachea: dynamics in response to herniation of the normal thymus. Radiology 1993;186 : 383-386[Abstract/Free Full Text]
  3. Adam EJ, Ignotus PI. Sonography of the thymus in healthy children: frequency of visualization, size, and appearance. AJR1993; 161:153 -155[Abstract/Free Full Text]
  4. Kim OH, Kim WS, Kim MJ, Jung JY, Suh JH. US in the diagnosis of pediatric chest diseases. RadioGraphics2000; 20:653 -671[Abstract/Free Full Text]
  5. Han BK, Suh YL, Yoon HK. Thymic ultrasound. I. Intrathymic anatomy in infants. Pediatr Radiol 2001;31 : 474-479[CrossRef][Medline]
  6. Loney DA, Bauman NM. Ectopic cervical thymic masses in infants: a case report and review of the literature. Int J Pediatr Otorhinolaryngol 1998; 43:77 -84[CrossRef][Medline]
  7. Morgan NJ, Emberton P. CT scanning and laryngocoeles. J Laryngol Otol 1994; 108:266 -268[Medline]
  8. Harnsberger RH. The larynx and hypopharynx. In: Harnsberger RH.Handbook of head and neck imaging, 2nd ed. St. Louis, MO: Mosby-Year Book, 1994:224 -260
  9. Kwok KL, Lam HS, Ng DK. Unilateral right-sided internal jugular phlebectasia in asthmatic children. J Paediatr Child Health 2000; 36:517 -519[CrossRef][Medline]
  10. Uzun C, Taskinalp O, Koten M, Adali MK, Karasalihoglu AR, Pekindil G. Phlebectasia of left anterior jugular vein. J Laryngol Otol 1999; 113:858 -860[Medline]

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 Am. J. Roentgenol.Home page
S. Senel, N. Erkek, and G. Cinar
Is It A Case Of Superior Herniation Of Normal Mediastinal Thymus?
Am. J. Roentgenol., November 1, 2007; 189(5): W301 - W301.
[Full Text] [PDF]

This Article
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wong, K. T.
Right arrow Articles by Ahuja, A. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wong, K. T.
Right arrow Articles by Ahuja, A. T.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS