Pulmonary multinucleate giant cells in dermatosis vegetans in swine: light microscopic and immunohistochemical investigations.

Five pigs with dermatosis vegetans (DV), aged 1–28 days, were examined with the purpose of describing the pulmonary changes and to characterize the pulmonary multinucleate giant cells (MGC) and their possible cytogenesis. No pulmonary changes were present at birth. From 7 days of age, lung changes were characterized by proliferation of alveolar epithelial cells and formation of MGCs. Immunostaining for cytokeratin by a peroxydase–streptavidin method gave a positive reaction in MGCs, bronchial, bronchiolar and alveolar epithelium. MGCs seemed to be formed in the course of alveolar epithelial proliferations, and type-II pneumocytes were proposed as possible precursors.