Background Heterotopic bone formation within a muscle is designated as 'myositis ossificans', and is associated with multiple etiologies, such as trauma, genetic predisposition, post-infection, or undetermined causes. Myositis ossificans has been described in far less than 100 cases in the head and neck region. If occurring in the head and neck region, masticatory muscles are commonly involved, and therefore symptoms regularly are related to impaired temporomandibular joint function. It has not yet been described as cause for eustachian tube obstruction and conductive hearing loss.

Methods Case report of the first reported case with eustachian tube obstruction and recurrent preauricular swelling as the leading symptom of heterotopic calcifications of the medial pterygoid and masseter muscle.

Results A 71-year old woman presented with conductive hearing loss due to otitis media with effusion and a swelling of the preauricular region on the right side for at least two years. Computed tomography and magnetic resonance imaging examinations revealed a calcified mass inside of the right medial pterygoid and masseter muscle. A myringotomy with placement of an ear tube on the right side was performed. The patient then was free of complaints and a follow up by computed tomography was performed 4 months later. The calcified mass presented stable without progress.

Discussion Myositis ossificans needs to be considered as a differential diagnosis in head and neck tumors. Because of its very rare occurrence, treatment for myositis ossificans is not well established. Surgical removal can be considered in symptomatic cases but may be challenging. In our case the leading symptom was an obstructive Eustachian tube dysfunction that could successfully be treated with ventilation tubes.

Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.