Air bag injury as a cause of inflammatory myofibroblastic pseudotumour of the subglottic larynx progressing to myositis ossificans.

Inflammatory myofibroblastic pseudotumour (IMFPT) is a rare condition. The clinical presentation can be indistinguishable from that of a malignant neoplasm. The most frequently affected organ is the lung; a much less common site is the larynx and subglottic involvement is particularly rare. Trauma is purportedly one potential aetiological factor, although there have been no previous reports of IMFPT occurring in the larynx secondary to external laryngeal trauma. We present a case of IMFPT of the subglottis which occurred subsequent to external trauma of the neck sustained during air bag inflation in a road traffic accident. This mechanism has not been previously reported. Furthermore, the lesion progressed uniquely to show myositis ossificans-like maturation over time. The patient was ultimately treated by means of complete local excision.