Method: Histological sections from paraffin blocks were used for hematoxylin-eosin and special stains (elastica-Masson trichrome, PAS, Geimsa, Grocott), for immunohistochemistry (antibodies against kappa and lambda light chains, CD20, CD3, IgG, IgM, IgA, IgG4, LMP1) as well as for EBER in situ hybridisation and PCR. Results: The lung tissue was irregulary fibrotic with dense lymfoplasmacytic infiltration concentrated in the walls of pulmonary arteries. Some arteries were obliterated by intimal fibrosis. Infiltrating lymphocytes were small and without atypias. The majority of lymphocytes were CD3 positive, nearly all plasmocytes showed IgG positivity. IgG4/IgG ratio was 60 %. EBER in situ hybridisation was negative and monoclonal reaarangement of T cell receptor or immunoglobulin heavy chain genes were not detected. Conclusion: IgG4-related lung disease is rare. Obliterative vasculitis and high percentage of IgG4 positive plasmocytes are main histological features of this entity. Objective: Primary lung carcinoma with heterotopic osteocartilaginous formation is exceedingly rare. To date only 38 cases have been reported in the literature and the pathogenesis is not fully investigated. We report a case of pulmonary adenocarcinoma with osteocartilaginous formation with immunohistochemical staining of bone morphogenetic proteins (BMPs). Method: A 59-year-old man was admitted to our hospital for a lung tumor in his left upper lobe. An open lung biopsy followed a lobectomy was done. The resected tissue was fixed with 10 % formalin and embedded in paraffin. Sections, cut from paraffin blocks, were subjected to hematoxylin and eosin (HE) staining and Masson-Goldner staining, in addition to immunohistochemical staining. Results: The tumor was poorly differentiated adenocarcinoma with heterotopic ossification. Some of the tumor cells were positive for BMP-2, 6, and 7. Some of mesenchymal cells in tumor interstitium were positive for osteoblast (OB)-cadherin or BMP receptor-IA. Conclusion: We report a case of primary lung adenocarcinoma with heterotopic osteocartilaginous formation and reviewed previously published reports. To our best knowledge, this was the first case that not only BMP was expressed in tumor cells but also OB-cadherin or BMP receptor in some mesenchymal cells of tumor interstitium.