- Department of Trauma and Emergency, All India Institute of Medical Science (AIIMS), Bhubaneswar, Odisha, India
- Department of Neurosurgery, All India Institute of Medical Science (AIIMS), Bhubaneswar, Odisha, India
Department of Neurosurgery, All India Institute of Medical Science (AIIMS), Bhubaneswar, Odisha, India
DOI:10.4103/2152-7806.138517Copyright: © 2014 Patnaik A. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Patnaik A, Mahapatra AK. Giant asymptomatic mastoid pneumocele producing a scalp swelling: A rare case report. Surg Neurol Int 11-Aug-2014;5:126
How to cite this URL: Patnaik A, Mahapatra AK. Giant asymptomatic mastoid pneumocele producing a scalp swelling: A rare case report. Surg Neurol Int 11-Aug-2014;5:126. Available from: http://sni.wpengine.com/surgicalint_articles/giant-asymptomatic-mastoid-pneumocele-producing-a-scalp-swelling-a-rare-case-report/
Background:Intraosseous collections of air are rare in comparison to the extra-osseous collection. Pneumoceles are rare entities defined as enlarged pneumatized air sinuses or air cells, with focal or diffuse thinning of the surrounding bony walls. They may affect mastoid air cells and any of the paranasal sinuses.
Case Description:We report a rare case of extensive mastoid pneumatisation in a young male patient. Patient was completely asymptomatic with swelling as the main complaint. Short history of development raised suspicion for a malignant lesion. Cholesteatoma was also taken as a differential diagnosis. However, computed tomography (CT) scan showed gross expansion of mastoid air cells with no lesion inside it. The walls of mastoid were markedly thinned out, making the diagnosis as pneumocele. In spite of a large swelling, conservative treatment was adopted in view of no symptoms and was advised follow-up regularly to detect any possible complications.
Conclusion:Our case was interesting in that rare mastoid pneumoceles can be totally asymptomatic and can be large enough to raise concern for a malignant lesion. Literature shows that such mastoid pneumocele are symptomatic and require active intervention. Our asymptomatic mastoid pneumocele is a rare instance requiring no surgical procedure and was followed-up. Overall, such lesions should be treated as normal variants of physiological mastoid.
Keywords: Giant, mastoid, pneumocele
Pneumoceles are rare and are included under the group of intraosseous collections of air along with hypersinus, pneumosinus dilatans. Pneumatoceles are extra-osseous collections and are caused by trauma, infection, tumor, or surgery.[
A 19-year-old male patient presented with a swelling over the right side mastoid region. The swelling was present in its small form for quite a long time but became conspicuous only for last 4-5 months. There were no symptoms other than swelling behind the right ear [
(a) CT Head showing grossly dilated mastoid air cells with thinning of surrounding bone. (b) CT bone window showing the enlarged and multiseptated appearance of the swelling. (c) Coronal CT cuts showing grossly enlarged mastoid. (d) 3D CT reconstructed image showing thinning and erosion of mastoid bone
Differential diagnosis of enlarged mastoid air cells includes hypersinus, pneumosinus dilatans. Pneumoceles are the intraosseous collections of air and are different from pneumatoceles, which are extra-osseous and caused by trauma, infection, or surgery. Pneumoceles are categorized along with pneumosinus dilatans and hypersinus as intraosseous collection of air. In both pneumosinus and hypersinus, collection of air produces enlargement of sinuses and mastoid without causing thinning of surrounding walls. A hypersinus is an enlarged sinus that does not expand the surrounding bone beyond its normal boundaries and has bony walls that are of normal thickness. Pneumosinus dilatans refers to a paranasal sinus with bony walls that are of normal thickness with focal or diffuse abnormal expansion of the sinus. Pneumoceles produce focal or generalized luminal enlargement and focal or diffuse thinning of the adjacent bony wall as in our case. Som and Bergeron[
Various proposed causes of pneumocele include developmental, inflammatory, neoplastic, and trauma. Persistently raised intraluminal or intrasinus pressure has been proposed as the basic mechanism of pneumocele formation.[
Treatment of pneumocele is symptom dependent, and the indications for surgical intervention include intractable headache, hearing loss with or without tinnitus, and atlanto-occipital dislocation. The treatment could be as simple as myringotomy with grommet insertion as reported by Martin et al. where trapped air was let out with improvement of symptoms and re-ossification with newly formed bony trabeculae and increased thickness of surrounding cortical bone.[
Pneumoceles are frequently large enough to produce mass effect on surrounding structures like external acoustic canal or may extend into surrounding bones and joints. These usually require surgical intervention, the type of which depends upon the type, site, and the bones involved. But, purely asymptomatic localized pneumocele like the present case, causing large retroauricular mastoid swelling without any other symptoms, is quite rare and needs attention. Such type of lesions, although raise a strong alarm in the patient concerned, are benign and can be managed conservatively.
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