Difficult to treat asthma is an asthma syndrome that brings in our mind other differentials. Mediastinal masses are not common findings, but are important variables. Bronchogenic cyst is a congenital anomaly of the foregut that is typically found in the mediastinum and diagnosed accidentally. We present a 4-year-old girl with allergic asthma that began at 8-months of age and finally a bronchogenic cyst was detected in this patient. The patient had history of asthma since she was eight months old. She had a history of several asthma attacks which had partly responded to asthma management.
During the last episodes of asthma attacks, she was hospitalized in Pediatric Intensive Care Unit. Imaging studies showed a 4×3 cm mass in the posterior part of the thoracic cavity that had led to tracheal narrowing was found for which the patient underwent thoracotomy and in surgical exploration a cyst that had compressed the thoracic trachea. Pathological examination of the cyst revealed a bronchogenic cyst. Bronchogenic cyst is an uncommon developmental abnormality but in a patient with obstructive pattern of airways it should be considered in differential diagnosis of asthma, especially if the asthma management is not successful.