Chest wall, mediastinal, pericardial, myocardial, lobar fissure and pleural locations of the hydatid cysts are referred to be intrathoracic extrapulmonary cysts. In this report a 20-year-old male patient had a liver dome cyst, which was opened into the diaphragm and caused diaphragmatic hydatid cysts. The scoleces have probably been transported by diaphragmatic lymphatics into the subpleural location and then hydatid disease has been disseminated via parasternal lymph nodes anteriorly and intercostal lymph nodes posteriorly towards cupola of the thorax. With regard to this localization, we propose a novel terminology as 'intrathoracic extrapleural hydatid cyst' and we hypothesize a novel dissemination theory for the hydatid cysts via diaphragmatic lymphatic drainage.