Spontaneous thoracic air-leakage syndrome in patients following allogeneic hematopoietic stem cell transplantation: Causes, CT-follow up and patient outcome

The purpose of this article is to describe and illustrate the acute and follow-up imaging features, clinical constellation and outcome of patients with thoracic air-leakage syndrome following allogeneic hematopoietic stem cell transplantation (allo-HCT).Patients with evidence of thoracic air-leakage, i.e. spontaneous pneumomediastinum, spontaneous pneumothorax or interstitial emphysema after allo-HCT were retrospectively identified by a chart review. Acute and follow-up morphology, duration and patient outcome were analyzed on CT (HRCT or MSCT with HR-reconstructions). Correlation was made with histological results of transbronchial biopsy.The 6 patients included (3 male and 3 female, 14-64 years old) with thoracic air-leakage after allo-HCT all had histologically proven bronchiolitis obliterans (BO) or bronchiolitis obliterans organizing pneumonia (BOOP). Thoracic air-leakage consisted of spontaneous pneumomediastinum associated with active invasive pulmonary aspergillosis (IPA) in 4/6 and spontaneous pneumothorax or interstitial emphysema each in 1/6 patients. Duration of thoracic air-leakage was 7-135 days. Of the patients with spontaneous pneumomediastinum, 3/4 died of IPA. One patient survived until complete regression of spontaneous pneumomediastinum. One patient died 7 days after spontaneous pneumothorax and one survived developing chronic interstitial emphysema.In all cases, thoracic air-leakage was associated to BO or BOOP. In the majority of cases with additional IPA, thoracic air-leakage is more indicative for severity of pulmonary disease than a life-threatening entity itself.