Objective: Parenchymal fibroelastosis in chronic fibrosing lung disorders has been much investigated, but little attention has been directed at the visceral pleura (VP) participation in these situations. Our aim was to verify whether elastic deposition accompanies collagen deposition in the repairing process of chronic lung injury. In this work we studied the distribution of these fibrous components of VP in bullous disease type I and II, smoking-related interstitial fibrosis and usual interstitial pneumonia (UIP). Method: We employed histochemical methods on conventional histological slides. We measured, by image analysis, the content of fibres of the collagenous and elastic systems of the visceral pleura in histological slides sampled from surgical lung biopsies and bullectomy, using the picrosirius-polarization method and Weigert's resorcin-fuchsin stain, respectively. Results: Four groups were studied: I, 7 patients with spontaneous pneumothorax due to type I bullous disease; II, 12 patients with spontaneous pneumothorax due to type II bullous disease; III, 5 smoking-related interstitial fibrosis; and IV, 5 patients with idiopathic pulmonary fibrosis. The first two groups were used as controls. Patient diagnosed with Idiopathic pulmonary fibrosis (2009), in which experimental transplantation was performed of type II pneumocytes, ingress to the hospital for further study groundmass of the right lung. In the postmortem study a 2340 gr. mass was identified, the mass was formed by sarcomatous cells habit, undifferentiated and pleomorphic, with the presence of multiple implants and adhesions in rib cage, diaphragm, pericardial fat. IHC profile was performed: vimentin (+), EMA focally (+), WT1, CK8, TTF1, CKAE1/AE3, S100, CD34, CD31 and CD45 (−) and low proliferation index, the diagnosis undifferentiated malignant tumor. With inconclusive IHC profile, so blocks were sent to Clinic Barcelona Hospital, for study. The estimated prevalence of idiopathic pulmonary fibrosis is 20 cases per 100,000 population in men, with a mortality of 50 % at 5 years of diagnosis. Cancer rate of in transplanted patients is within the range between 4 % and 18 %. Could the appearance of this tumor be related either to transplanted pneumocytes or it is inmunosupression the main risk factor? Current treatments for idiopathic pulmonary fibrosis are not effective, which requires the study and development of new therapeutic options, using fibroblast proliferation inhibitors, as well as prospective studies, in the long term, the evolution of these patients and the development of secondary entities to it. Objective: Mediastinal hemangiomas are rare tumors accounting for 0,5 % of all mediastinal tumors. These tumors are challenging because of the lack of clinical and radiologic specific signs. Their diagnosis is mainly based on microscopic study. Method: We report a 10-year-experience of a single institution. We describe 5 cases of mediastinal hemangioma. Results: Our study contained 2 men and 3 women with a mean age of 60.4 years. Symptoms consisted mainly in chest pain. Neurologic signs were observed in 2 patients. Surgical treatment was performed in all patients dealing with a total resection in 4 patients. The most used surgical approach was a posterolateral thoracotomy. Video-assisted thoracic excision was tried in one patient and was converted into a median sternotomy. Microscopic examination concluded to a mediastinal hemangioma in all cases. All the patients presented no complications after a follow up periods varying from 9 months to 2 years. Conclusion: Mediastinal hemangiomas are rare tumors whose diagnosis is based on microscopic findings. Their surgical management may be challenging because of their connection to the adjacent structures. Video-assisted thoracic excision is being more frequently used by experienced surgeons. These tumors are benign with a good behavior. Objective: Actinomycosis is an infectious disease caused by Actinomyce israeli in 85 % of the cases. It is mainly observed in alcoholic patients and affects mainly cervicofacial, abdominal and thoracic regions. Pulomnary actinomycosis accounts for 15 % of the localizations and is caused by the inhalation of septic particles causing granulomatous lesions, the extension to the adjacent organs and a cutaneous fistulae. It represents a real pitfall and mimics malignant lesions, tuberculosis or other infectious diseases. Method: We report a retrospective study about 6 cases of pulmonary actinomycosis diagnosed over a 17-year-period. Results: We describe the cases of 6 men aged between 35 and 46 years who presented with respiratory signs. Radiologic investigations showed in all cases parenchymal masses with irregular margins mimicking malignant processes. Positivie diagnosis was based on microscopic examination. The treatment was based on surgical excision associated to a medical treatment without complications after a follow up period ranging from 3 months to 18 months. Conclusion: Pulmonary actinomycosis shares usually the same clinical and radiologic features as malignant lesions.