[Reversible pulmonary hypoperfusion following proximal bronchial obstruction caused by a benign process].

Obstruction of a major bronchus by a benign lesion can be accompanied by a functional reduction of the perfusion of the distal lung. This disorder is reversible after removal of the obstruction. We present 5 cases of obstruction of a main bronchus with functional exclusion of the affected lung on scintigraphy. The obstructing lesion was carcinoid tumour in 4 cases and a plasmocytic granuloma in another case. The perfusion was found to be restored following the operation (one bronchotomy, three isolated resection-anastomoses and one resection-anastomosis with lobectomy). These disorders are due to reflex phenomena and anatomical modifications related to the trapping effect. These phenomena are revealed by plain chest x-rays and by perfusion and ventilation pulmonary scintigraphy.