Tracheal leiomyoma

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Airway tumours, including tracheal leiomyoma, should be considered in patients being treated for asthma who present with symptoms atypical of asthma, such as dyspnoea with position changes and stridor on inspiration, or who do not respond to conventional therapy. A 74-year-old woman with a history of allergic rhinitis was referred to our department for treatment-resistant asthma. She had been aware of dyspnoea on exertion for ∼5 years and had been experiencing stridor for several months when lying down at night, especially in the prone position. Although she had been treated for bronchial asthma, her symptoms did not improve. The patient was a non-smoker and maintained an oxygen saturation of 96%; however, further examination revealed stridor upon inspiration. Chest radiography showed no apparent abnormality (Figure 1a), while a plateau at high and medium displacements, which is considered an upper airway stenosis pattern, was observed during spirometry. Chest computed tomography (CT) showed a 30 mm × 10 mm mass in the trachea at the thyroid gland-level causing airway stenosis (Figure 1b and c). Further, CT in the prone position revealed a wide base of the mass and progressive airway narrowing (Figure 1d). A smooth hyper-vascularized tumour arising from the membranous area under the glottis was observed via bronchoscopy (Figure 1e) and subsequent biopsy led to the diagnosis of leiomyoma. While the tumour was benign, early therapeutic intervention was necessary due to the presence of stridor and dyspnoea. (a) Chest radiography initially appeared normal but was reinterpreted to reveal a mass in the trachea outside the thorax upon further review. (b) Chest CT of sagittal view showed a mass in the trachea at thyroid gland-level and a stenotic trachea. CT of the patient on supine (c) and prone (d) revealed an exacerbation of tracheal stenosis in the prone position. (e) Bronchoscopy showed a smooth-surfaced mass under the glottis. Given the high risk of choking due to bleeding, as well as the tumour’s wide base, bronchoscopic resection was deemed difficult. Similarly, intubation was also considered impossible as it was problematic to secure the airway because of the tumour size and location below the glottis. Fortunately, because the tumour was located at the thyroid gland level, we attempted to secure the airway through tracheotomy. Under general anaesthesia, tracheotomy was performed in the trachea below the tumour, followed by tumour resection using a direct laryngoscope. Histopathologically, the lesion was composed of intersecting smooth muscle bundles without necrosis or malignancy. Post-operatively, subjective symptoms such as stridor and dyspnoea improved despite the termination of asthma treatment. The patient remained asymptomatic and recurrence was not observed up to 18 months post-surgery. Primary tracheal tumours are rare, with leiomyomas accounting for only 1% of them.1 Tracheal leiomyomas arise from smooth muscle cells in the membranous part of the trachea and usually grow as polyp-like masses. They cause chronic cough, phlegm, dyspnoea and abnormal breath sounds such as stridor and wheezing, and are often treated as asthma because they are benign tumours that grow slowly, have a long progression, and present similar symptoms.2,3 This can delay accurate diagnosis, allowing severe symptoms to manifest due to airway obstruction.3,4 Findings that are suggestive of tracheal obstructive lesions include the following: recent onset of asthmatic wheezing in patients aged >40 years, especially if the wheezing is more marked on inspiration; paroxysmal attacks of wheezing that are relieved or precipitated by a change in position; lack of response to the usual anti-asthmatic therapy; haemoptysis with asthmatic wheezing; and orthopnoea and/or paroxysmal nocturnal dyspnoea in the absence of significant cardiovascular disease.3 Of these findings, sudden wheezing with positional changes and nocturnal paroxysmal dyspnoea may be related to changes in tumour location and accumulation of secretions.3 Furthermore, position-related sudden shortness of breath and wheezing have also been reported in other cases of tracheal tumours.5 In our case, progressive airway narrowing due to a shift in tumour position during prone orientation was observed on CT. Furthermore, exacerbation of dyspnoea is suspected to be the result of physical airway obstruction by this shift. Comparison of supine and prone CT may provide a visual understanding of the change in degree of airway obstruction with body position. In summary, clinicians should consider airway tumours, such as leiomyomas, in patients being treated for asthma and presenting with atypical asthma symptoms. Informed consent for publication of this case report was obtained from the patient. This study did not receive any funding. Conflict of interest: None declared.

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