Abstract

A rare case of solitary plasmacytoma of the lung in a 66-year-old woman is presented. The diagnosis was made after a pneumonectomy for the presence of a mass in the left lung. The light microscopic, ultrastructural and immunohistochemical studies were done. Microscopic examination revealed sheets of well differentiated plasma cells interspersed with markedly atypical plasma cell. Peroxidase-antiperoxidase staining and immunofluorescent studies showed the neoplastic plasma cells to be producing a monoclonal immunoglobulin (Ig M, kappa). Ultrastructural examination showed neoplastic plasma cells packed with rough endoplasmic reticulum cysternae which were markedly dilated and filled with homogeneous, moderately electron-dense material. A brief review of the literature was done.