Mesothelioma of the pleura remains an incurable disease for which novel treatments are being investigated. One of these is intraoperative photodynamic therapy (PDT), using the principle of cell cytotoxicity produced by light-activated sensitization. We report a complication of this therapy that defined the maximal tolerated dose of PDT, ie, esophagopleural fistula, in two consecutive patients who had received the same dose of PDT at the time of extrapleural pneumonectomy.