CASE REPORTS
A Retropharyngeal Lipoma Causing Obstructive Sleep Apnea in a Child Weixi Gong, M.S.1; Entong Wang, M.D., Ph.D.1; Baolin Zhang, M.D.1; Jiping Da, M.D., Ph.D.2 The Department of Otolaryngology, Head & Neck Surgery and 2The Department of Pathology, The General Hospital of the Air Force of PLA, Bejing, China
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Background: Lipomas are common benign tumors, but they rarely occur in the retropharyngeal space and even more rarely occur in children. Case report: We report the case of an 11-year-old girl with a 5-year history of progressively worsening nasal obstruction, snoring, and excessive daytime sleepiness. Physical examination revealed a child with a body mass index of 16.9 kg/m2; otolaryngologic examination and imaging studies showed a large retropharyngeal mass. Polysomnography indicated an apnea-hypopnea index of 13.9 events per hour of sleep and a minimum oxygen saturation of 84%, with 20 episodes of desaturation to less than 90%. After complete excision of the mass, the patient’s snoring,
apnea, and daytime sleepiness resolved. Conclusions: Although lipomas in the retropharyngeal space are rare, clinicians should be alert to the possibility of this condition occurring in children who have symptoms of obstructed breathing during sleep but a normal body mass index and no other risk factors for obstructive sleep apnea. Keywords: Lipoma, obstructive sleep apnea, polysomnography Citation: Gong W; Wang E; Zhang B et al. A retropharyngeal lipoma causing obstructive sleep apnea in a child. J Clin Sleep Med 2006;2(3):328-329.
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Imaging Studies
ipomas are commonly occurring benign tumors. Although approximately 13% of these tumors occur in the head and neck, they are rarely found in the retropharyngeal space. Retropharyngeal lipomas grow slowly and do not cause symptoms until they reach a large size. Initial symptoms are often related to airway obstruction, including obstructed breathing during sleep.1-3 We present a case of a child with obstructive sleep apnea (OSA) secondary to a lipoma in the retropharyngeal space.
A lateral cephalometric radiograph and a computed tomography (CT) scan revealed a retropharyngeal mass extending from the nasopharyngeal roof down to the level of the fourth cervical vertebra, measuring 8 cm × 4 cm × 2 cm, and narrowing the upper airway. The CT showed a homogeneous, low-attenuation, welldefined mass with multiple intrinsic septa, compatible with fat tissue. No invasion of the surrounding structures was noted (Figure 1). A preliminary diagnosis of lipoma in the retropharyngeal space was made, although aspiration biopsy was not performed.
REPORT OF CASE An 11-year-old girl presented with progressively worsening nasal obstruction, snoring, and excessive daytime sleepiness over the past 5 years. The mother noted that, over the past 2 years, her daughter had sometimes seemed to struggle for air during sleep. Both the mother and the daughter reported that the patient had no other medical problems. Physical examination showed that the patient was very thin and short for her age, with a weight of 38 kg and a height of 150 cm, yielding a body mass index of 16.9 kgm2. On oral examination, a large retropharyngeal submucosal mass was visible and palpable. The overlying mucosa was intact and normal. No adenotonsillar enlargement was noted.
Polysomnography The child underwent overnight polysomnographic testing,
Disclosure Statement This was not an industry supported study. Drs. Gong, Wang, Zhang, and Da have indicated no financial conflicts of interest. Figure 1—Left: Lateral neck radiograph showing a large mass in the retropharyngeal space, extending from the nasopharyngeal roof to the level of the fourth cervical vertebra, narrowing the upper airway. Right: axial computed tomography image at the level of the palate showing a homogeneous and hypodense mass with multiple intrinsic septa.
Submitted for publication July 2, 2005 Accepted for publication December 30, 2005 Address correspondence to: Weixi Gong, 30 Fucheng Road, The Department of Otolaryngology, Head & Neck Surgery, The General Hospital of the Air Force, Haidian District, Beijing 100036, P. R. China; Tel: 0086 10 68471316; E-mail:
[email protected] Journal of Clinical Sleep Medicine, Vol. 2, No. 3, 2006
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Retropharyngeal Lipoma Causing OSA
OSA is a common condition in children, with a prevalence of about 1% to 3%.7 Polysomnography is currently the gold standard for the detection and assessment of the severity of OSA, but adult criteria for OSA are not applicable to children.8 Therefore, OSA in children has been defined as an obstructive apnea index of 1 or more events per hour of sleep,9 with severity criteria being defined as mild (1-4/hour), moderate (5-9/hour), and severe (≥10/ hour).10 In the case presented here, the patient would have severe OSA according to these criteria. In children, the most common cause of upper-airway obstruction and, therefore, OSA is adenotonsillar enlargement. Severe upperairway obstruction in children may result in the delay of growth and development. As was found in the case of our patient, when the apnea is adequately treated, affected children typically have an improvement in both weight and height.9 However, not all airway obstruction in children is due to adenotonsillar enlargement. In this case, our patient had a history strongly suggestive of OSA but no evidence of adenotonsillar enlargement. Although retropharyngeal lipoma is a very rare cause of OSA in children, this case of an 11-year-old girl with OSA caused by a lipoma in the retropharyngeal space should alert clinicians to consider the possibility of a retropharyngeal lipoma in the differential diagnosis in children with OSA.
including electroencephalography, electromyography, electrooculography, electrocardiography, oronasal airflow, abdominal and chest-wall movement, body position, snoring sound, and arterial oxygen saturation (SaO2). End-tidal CO2 testing was not available. Following the diagnostic criteria of the International Classification of Sleep Disorders,4 an apnea was defined as a cessation of oronasal airflow for more than 10 seconds, and a hypopnea was defined as a decrease in airflow to less than 50% of the baseline amplitude. Results of polysomnography showed that the time and percentages of time spent in sleep stages 1, 2, 3, 4, and rapid eye movement (REM) were 51 minutes (10.4%), 266.5 minutes (54.5%), 79 minutes (16.2%), 51 minutes (10.4%) and 41.5 minutes (8.5%), respectively. Four arousals occurred and lasted for a total of 15 minutes. The snoring index was 32.1. During sleep, the patient had 103 apneic events, lasting for a total of 38 minutes, with the longest apnea having a duration of 70 seconds. Fifty apneic events occurred in non-REM sleep, and the remaining 53 occurred during REM sleep. An additional 11 hypopneic episodes, totally 4.4 minutes in duration, occurred, with 8 in non-REM and 3 in REM sleep. The apnea and hypopnea indexes were 12.6 per hour and 1.3 per hour, respectively. All apneas and hypopneas were obstructive, and most occurred when the patient was in the supine position. The lowest SaO2 was 82%, and the oxygen desaturation index below 90% was 2.5, with a total of 20 episodes of desaturation. No cardiac arrhythmia or abnormal blood pressure was detected. Thus, a diagnosis of OSA was determined by polysomnography.
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Aland JW. Retropharyngeal lipoma causing symptoms of obstructive sleep apnea. Otolaryngol Head Neck Surg 1996;114:628-30. 2. Di Girolamo S, Marinelli L, Galli A, Ottaviani F. Retropharyngeal lipoma causing sleep apnea syndrome. J Oral Maxillofac Surg 1998;56:1003-4. 3. Hockstein NG, Anderson TA, Moonis G, Gustafson KS, Mirza N. Retropharyngeal lipoma causing obstructive sleep apnea: case report including five-year follow-up. Laryngoscope 2002;112:16035. 4. International Classification of Sleep Disorders: Diagnostic and Coding Manual. Rochester: American Sleep Disorders Association; 1997. 5. Shivakumar AM, Naik AS, Shetty DK, Yogesh BS. Lipoma of the retropharyngeal space. Indian J Pediatr. 2004;7:271-2. 6. Kransdorf MJ, Bancroft LW, Peterson JJ, Murphey MD, Foster WC, Temple HT. Imaging of fatty tumors: distinction of lipoma and welldifferentiated liposarcoma. Radiology 2002;224:99-104. 7. Ferini-Strambi L, Fantini ML, Castronovo C. Epidemiology of obstructive sleep apnea syndrome. Minerva Med. 2004;95:187-202. 8. Rosen CL, D’Andrea L, Haddad GG. Adult criteria for observation sleep apnea do not identify children with serious obstruction. Am Rev Respir Dis 1992;146:1231-4. 9. Marcus CL, Carroll JL, Koerner CB, Hamer A, Lutz J, Loughlin GM. Determinants of growth in children with the obstructive sleep apnea syndrome. J Pediatr 1994;125:556-62. 10. Katz ES, Greene MG, Carson KA, et al. Night-to-night variability of polysomnography in children with suspected obstructive sleep apnea. J Pediatr 2002;140:589-94.
Treatment In anticipation of a potentially difficult orotracheal intubation, a tracheotomy was performed, and general anesthesia was delivered through the tracheal tube. The retropharyngeal mass was excised transorally and sent for pathologic examination, with subsequent histologic confirmation of the preoperative diagnosis of lipoma. The patient was extubated on the day after surgery and began taking food orally. One week after surgery, the patient left the hospital after an uncomplicated postoperative course. The preoperative symptoms of snoring, apneic episodes, and daytime somnolence had completely resolved. A follow-up visit at 6 months showed a well-nourished 11-year-old, with a weight of 46.5 kg, a height of 157 cm, and a body mass index of 18.9 kg/m2. Follow-up polysomnography could not be performed because of cost constraints. DISCUSSION Lipomas, which are slow-growing mesenchymal tumors, are common in adults but are not often seen in children.5 Lipomas in the retropharyngeal are rare and usually become quite large before producing symptoms of airway obstruction. Management is typically via surgical excision.3 CT scans are helpful in the preoperative assessment of the patient prior to definitive pathology examination of a lipoma. On CT, lipomas have characteristic homogeneous fatty attenuation (-50 to -150 Hounsfield values), with variable margins and thin fibrous septa of low signal intensity on T1- and T2-weighted images.6 CT cannot definitively distinguish a lipoma from a liposarcoma; therefore, liposarcoma should be considered in the differential diagnosis.3,7 Journal of Clinical Sleep Medicine, Vol. 2, No. 3, 2006
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