Cavity of Primary Lung Cancer

Characteristics of clinical and radiological findings of primary lung cancer with cavity were studied on 23 cases admitted to our clinic in the past 10 years. Incidence was higher in the fifth and sixth decades and more common in male than female (2.3:1). Histological types of these 23 cases were squamous cell carcinoma (15 cases), adenocarcinoma (5 cases) and undifferentiated carcinoma (3 cases). The mechanism of cavity formation seemed to be different among these histological types of lung cancer.The size of cavity was over 4cm in diameter in 10 out of 15 cases of squamous cell carcinoma and one half of the cases had distinct clinical and laboratorical evidences of concomitant infection. Contrarily, no such inflammatory findings were seen in the other 5 cases of squamous cell carcinoma where tumor was under 4cm in diameter.All of the 3 cases of undifferentiated carcinoma (tumor was over 8 cm in 2 cases and 4cm in 1 case in diameter) showed definite evidence of inflammation.These findings indicated a possible mechanism of cavity formation in these two histological types of lung cancer, that necrosis would occur in consequence of ischemic changes which would appear when the size of tumor became larger than 4cm in diameter, and in addition to this, infection of the part would accelerate the formation of the cavity. On the other hand, the cavity was observed in all cases of adenocarcinoma in spite of the size of tumor being about 4cm in diameter or less: From these histological findings, it was thought that the main factor of cavity formation in this type of lung cancer would be the ischemic necrosis in the tumor.