Malignant pulmonary neoplasms predisposing to pneumothorax

Correspondence to: Saulius Cicėnas, Department of Thoracic Surgery and Oncology, Institute of Oncology, Vilnius University, Santariškių 1, LT-08660 Vilnius, Lithuania. E-mail: saulius.cicenas@vuoi.lt Bachground. The main purpose was to point out pneumothorax (P) as the first symptom of thoracic malignancy. The mechanisms by which pneumothorax occurs in lung cancer are not clear. Materials and methods. From 1970 to 2009, 42 cases of pneumothorax as the initial symptoms of lung cancer were diagnosed at the Department of Thoracic Surgery and Oncology, Institute of Oncology, Vilnius University. In 27 patients (64.3%), pneumothorax occurred in primary lung carcinoma (LC) and 15 patients (35.7%) in metastatic LC. The mean age was 53.7 years. The morphology of LC was as follows: squamous cell carcinoma 17 cases (40.4%), adenocarcinoma 6 cases (14.3%) and small cell carcinoma 5 cases (11.9%). Morphology in the group of 15 metastatic cases (35.7%): 2 cases of metastatic angiosarcoma, 3 cases of chondrosarcoma, 4 cases of seminoma, 4 cases of renal cancer and 2 cases of metastatic synovial sarcoma. Results. Pleural drainage with chemotherapy was used for 16 patients (38.0%), 21 patients (50.0%) underwent thoracotomy, and 5 patients (11.9%) video-assisted thoracic surgery (VATS). Complications were noted in 10 patients (23.8%). Pneumothorax was cured in 41 patients (97.6%), and 1 patient (2.4%) died. In 16 patients (38.0%) the lung was expanded by drainage, 21 (50.0%) underwent surgery and 5 patients (11.9%) minimal invasive surgery (VATS), 14 patients (33.3%) underwent chemoradiation after lung recovery. Median survival of the patients was 31 months. Conclusions. Pneumothorax as the first manifestation of LC appears not often but may have dangerous complications.


INTRODUCTION
Pneumothorax (P) as the first sign of bronchial carcinoma is a rare complication with a poor prognosis.The estimated rate of joint occurrence varies between 0.03 and 0.05% of primary lung cancer (1).The main factor in the etiology of SP could be related to tumour lysis and a rapid rupture, or a subpleural metastasis into the pleural cavity, thus leading to a bronchopleural fistula (2).
Pneumothorax in primary lung cancer is rare, and its prognosis is poor.Lung cancer should always be considered as a possible cause of pneumothorax, and it is important to diagnose cancer as early as possible.

MATERIALS AND METHODS
In 1970-2009, 42 cases of P as the first manifestation of lung cancer were diagnosed at the Department of Thoracic Surgery and Oncology, Institute of Oncology, Vilnius University.In 27 patients (64.3%),P occurred in primary lung carcinoma (LC) and in 15 patients (35.7%) in metastatic LC.Patients' distribution by sex: 30 (71.4%) males and 12 (28.6%)females.Their mean age was 53.7 years.
Pneumothorax was cured in 41 patients (97.6%), and one patient (2.4%) died.The median survival of patients was 31 months.Fourteen patients (33.3%) underwent chemoradiation after lung recovery (Table ).The association between pneumothorax and lung cancer is very rare, expecially in the abscence of other radiological disorders suggesting neoplasia after pulmonary reexpansion.In these cases, the diagnosis is extremely difficult and must be always suspected in patients with P and at risk of pulmonary cancer.

DISCUSSION
Pneumothorax can be classified as primary and secondary.Primary P is usualy characterized by a rupture of a bleb in the lung, while secondary P mostly occurs due to chronic obstructive pulmonary disease (COPD) with emphysematous bullae, tuberculosis, pneumonia, asthma, cystic fibrosis, lung cancer, interstitial lung disease, lymphangioleiomyomatosis (1-3).
Pneumothorax as the initial manifestation of bronchial carcinoma is a rare complication with a poor prognosis.Considering that only 2% of all P coexist with malignant lung diseases (either primary or secondary), this tumour complication must be especially suspected in older patients.Their prognosis may be improved entirely by a rapid diagnosis and therapy (4).
The mechanism of pneumothorax from lung cancer is not well understood, but several theories have been advanced.One concept is that it may be a result of tumor necrosis -a rupture of the necrotic neoplastic tissue in the pleural cavity (9).
Rupture of a necrotic tumour nodule or necrosis of subpleural metastases produce a bronchopleural fistula which results in pneumothorax (5).The next theory, cancer of the check valve mechanism tumor at the lung periphery can obstruct bronchioles and lead to a local overdistention and rupture of the lung (10).
Most patients with lung cancer have chronic bronchitis or emphysemic bullae, and these bullae may rupture following the disturbance of lung architecture due to bronchial cancer (11).
Pneumothorax related to therapy has been reported in patients receiving chemotherapy and / or radiotherapy for lung cancer (12).There is a possibility that P and lung cancer are two independent and incidental processes.These conceptions suggest that lung cancer should always be considered as a possible cause of P in older patients.

CONCLUSIONS
Pneumothorax as the first manifestation of lung cancer appears not often, but has dangerous complications.

Results of SP treatment Methods and treatment Number of patients Recovery Died
Ta b l e.