We report the case of a woman with a metastatic breast cancer, who started a third-line treatment with dasatinib, a new oral tyrosine kinase inhibitor, and who developed, one week later, a progressive breathless sensation. Workup demonstrated pleuropericardial effusion that turned out to be a side effect of this new investigational drug. Although this dasatinib-induced side effect is well known, this case clearly illustrates the importance of an accurate diagnosis and adequate treatment of complications of new agents which are easy to use since most of them are orally taken, and the difficulty to clearly separate drug origin and cancer morbidities. The patient recovered completely one month after discontinuation of dasatinib. In this report, we will review the differential diagnosis and management of pleuropericardial effusion.