A 27-month-old boy was referred from one of our district hospitals to the Pietersburg tertiary hospital with an assessment of an acute asthmatic attack. The child was in severe respiratory distress and not responding to therapy, which included salbutamol nebulisations and oral prednisone. The child did not have a history of haemoptysis, fever, dysphagia, diarrhoea or weight loss. There was no history of tuberculosis contact in the household. He was fully immunised with normal milestones and good nutrition. 
 Previous admissions could not be elicited although he was treated on a few occasions by his general practitioner for recurrent chest infections and noisy breathing prior to this admission. The therapy at the time included salbutamol syrup, which is not standard therapy for asthma, oral prednisone and antibiotics; with no improvement. 
 Two months before this presentation he was diagnosed with asthma at a district hospital where he was treated with budesonide metred dose inhaler (MDI) 100 microg twice a day and 2 puffs of salbutamol MDI 100 microg when needed. However, there was minimal clinical response to this therapy, with persistence and worsening of symptoms. 
 Clinical examination on the day of admission revealed severe respiratory distress as evidenced by nasal alar flaring, intercostal and subcostal recessions. The child was not cyanosed but had signs of superior vena caval syndrome as evidenced by distended neck veins, cough, facial swelling and hoarseness of voice. He had no signs of chronic lung or cardiac disease but had significant lymphadenopathy  (>2 cm) involving axillary and inguinal regions. He had audible wheezes, with tracheal tug and a hoover sign. His heart sounds were normal, with no signs of pulmonary hypertension. Vital data monitoring while on oxygen by face mask showed saturations of 80%, a respiratory rate of 67 breaths per minute and heart rate of 182 beats per minute. 
 The patient was intubated and ventilated in the paediatric intensive care unit (PICU) and commenced on oral prednisone and nebulised with fenoterol and ipratropium bromide hourly as a continuation of asthma therapy while looking for an alternative diagnosis. He was started on second-line antibiotics, tazocin and amikacin and required sedation with dormicum and morphine. 
 The initial assessment was that of an intrathoracic airway obstruction secondary to a mediastinal mass and a respiratory tract infection. 
 The following investigations were performed: 
Chest X-ray, which confirmed that the endotracheal tube was in situ. It also showed widening of the mediastinum (Figs 1 and 2)
Urgent computerised axial tomography (CAT) scan of the chest (Figs 5 - 9)
Blood gas analysis, which documented respiratory acidosis. 
Additional haematological tests (urea and electrolytes, full blood count, liver function, blood cultures and C-reactive protein) were mostly normal, with two exceptions - a high C-reactive protein of 172 ml/L and Klebsiella pneumoniae and Candida fumata were cultured from blood. The infections were treated appropriately.
 The differential diagnosis at this point included tuberculous adenitis, lymphoma, bronchogenic cyst and thoracic neuroblastoma. 
 The mass was deemed to be exerting pressure on the oesophagus because, despite the insertion of a nasogastric tube, the child continued to vomit feeds. 
 The cardiothoracic surgical team was consulted and a diagnosis of a bronchogenic cyst was made. A thoracotomy was performed on day four of admission. Intraoperative findings were consistent with an intrathoracic cyst. A cystectomy was performed and an infected  cyst was removed. Ventilation of the patient in PICU was continued postoperatively. The postoperative course was eventful - a new fungal sepsis was identified and managed. A surgical relook procedure and bronchoscopy were performed and the intraoperative findings did not show any collections or puss in the excised cystic area. Bronchoscopy revealed a left bronchomalacia, with thick secretions (Fig. 12). 
 The patient was successfully ventilated for thirty days in PICU. At the time of submission of this manuscript for publication, the patient  was well and not receiving any treatment for asthma. Post discharge control chest X-rays and CAT scan of the chest were normal. 
 Macroscopically, the specimen consisted of an opened cyst that measured 70 x 45 mm. Microscopic examination of the cyst showed a fibromuscular wall and a respiratory epithelium lining, with areas of squamous metaplasia. Cartilage was focally present in the wall. The cyst was multilocular with acute on chronic inflammation and destruction of epithelial lining and was identified as a mediastinal BC.