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.