Pulmonary hamartomas mimicking metastatic carcinomas H. Erdem * , L. Yilmaz Aydin, A. K. Uzunlat, M. Oktay, A. N. Annakaya, U. Yilderim, F. Basar * Duzce University, Dept. of Pathology, Turkey Pulmonary hamartomas are usually found incidentally and they mimick metastic tumours. We report a case of a 47 year-old man who admitted to Chest Disease service for cough. He had laryngectomy operation formerly and diagnosed as squamous cell carcinoma. Chest-X-ray and computed tomography revealed pulmonary nodules. It was removed but there was not metastatic carcinomas. This case was presented because it can be difficult to make diagnosis when the patient has malignancy. Objective: Experimental models of pulmonary fibrosis (PF) has been proposed and its later phase tend to the resolution in different degrees depending on the drug/ strain/inflammatory-pattern. Thus the maintenance of these mechanisms may participate in the PF-progression. Our objective was to determine the immune-fibroticpattern in models of pulmonary fibrosis in the late stage (21d). Method: Distinct animal models were used, including Balb/c, C57BL/6 and IL17RA-KO-C57BL/6 mice by Bleomycin and Paraquat. We analyzed the amounts of total peribronchiolar-interstitial collagen (TPC-TIP) by picrosirius and Col3-Col5 by immunofluorescence through the morphometric evaluation. These data were validated by RT-PCR. Results: The TPC did not differ between the treated groups. TIC was higher in the C57BL/6 strain, independent of the absence of IL-17RA. The Col5-immunoexpression was higher in control and BLM-treated IL17RA-KO-C57BL/6 than in wild-mice and lower in BLM-Balb/c mice. The Col3immunoexpression was higher in BLM-Balb/c. Likewise, the Col5 gene expression was higher in the IL17RA-KO mice and lower in the BLM-Balb/c. Conclusion: The perpetuation of fibrosis in PF-susceptiblemice can be modulated by IL-17-dependent Col5-hiperexpression and by Col3-subexpression. This suggests that Col5 is an important component responsible for the development of PF.