Vibroacoustic Disease and Respiratory Pathology: IV - Lung and Pleura in a Lung Cancer Patient

摘要

BACKGROUND. Low frequency noise (LFN) (≤500 Hz, including infrasound) is a known genotoxic agent. To date, 10 vibroacoustic disease (VAD) patients, have developed squamous cell carcinomas in the respiratory tract. In this report, fragments of lung and pleura of a VAD-lung cancer patient are studied through light and electron microscopy. METHODS. The patient was a retired, 62-year-old male Caucasian, smoker, and employed as an aircraft technician for over 30 years. With the patient's informed consent, fragments of lung and pleura were removed during lung carcinoma surgery. Specimens were prepared for light microscopy and transmission electron microscopy (TEM). RESULTS. Thickened vessel walls were identified. Numerous macrophages were seen in the bronchioli and remaining lung parenchyma, some with brown pigment, and others with tar. TEM disclosed a marked reduction of type-I-pneumocytes, and a large increase of type-II-pneumocytes. Interstitial fibrosis was not uniformly distributed, but in some fields it was very prominent. Cells under apoptotic processes were very common. The most remarkable feature seen in the pleura was the increased thickness due to the intense collagen proliferation. DISCUSSION. The increased amount of focal fibrosis and of pleura and vessel wall thickening is an expected situation since the same has already been observed in LFN-exposed rodents. The reduction of type-I-pneumocytes and an increase in type-II-pneumocytes is also seen in other pulmonary stress situations. The very frequent images of apoptotic processes in the remaining parenchyma lung tissue were unexpected, and indicate possible avenues of research in the future.