hydropneumothorax

noun

hy·​dro·​pneu·​mo·​tho·​rax ˌhī-drə-ˌn(y)ü-mə-ˈthō(ə)r-ˌaks, -ˈthȯ(ə)r- 

plural hydropneumothoraxes or hydropneumothoraces -ˈthōr-ə-ˌsēz, -ˈthȯr- 

: the presence of gas and serous fluid in the pleural cavity

called also pneumohydrothorax