[Moderately differentiated adenocarcinoma of the lung presenting as multiple intrapulmonary metastases with thin-walled cavities].

A 63-year-old woman complaining of a non-productive cough was referred to our hospital. A chest X-ray film and computed tomographic scan showed a large mass in the S9 region of the right lung, and many intrapulmonary nodules with thin-walled cavities. A transbronchial biopsy specimen revealed moderately differentiated adenocarcinoma of bronchial gland origin. By the end of four cycles of chemotherapy with vindesine, ifosfamide, and cisplatin, the primary mass had markedly regressed, the many metastases had disappeared, and a few bullous lesions remained. On the second admission, many intrapulmonary metastases and cavities were seen again. Although some of the cavities may have been associated with regrowth of residual cancer cells around the remaining bullae, some nodules showed newly-developed thin-walled cavities, and in others bullous lesions developed again. These observations indicate that a check valve mechanism may operate in the formation of the thin-walled cavities.