[Atypical pleural effusion by transdiaphragmatic communication. Apropos of two cases: chylothorax and hydrothorax]

We report two cases of pleural effusion in which a subdiaphragmatic cause was noted. In both cases it was necessary to obliterate a defect in the diaphragm via a thoracic incision. In one case, a left chylothorax occurred in a patient with hepatic cirrhosis. In this case, it was postulated that the normal lymphatic pathway through the right hemidiaphragm could have been stopped by pleural sequelae from right lobectomy. In the other case, a right pleural effusion occurred after peritoneal dialysis. It is a well known pathological entity: the structural defect can be observed by separation of collagen bundles in the tendinous diaphragm. This type of pleuro-peritoneal communication is well known in women suffering from menstrual pneumothorax or in patients treated by peritoneal dialysis.