A novel differential diagnosis for diffuse cavitating nodules: primary pulmonary plasmacytoma

Abstract Background Extramedullary plasmacytoma is a rare monoclonal plasma cell neoplasm that originates from tissues other than the bone marrow and constitutes only 3%–5% of all plasma cell neoplasms. Most cases involve the upper respiratory tract. Extramedullary plasmacytoma involving the lung is extremely rare. Primary pulmonary plasmacytoma is a rare type of extramedullary plasmacytoma, usually presenting with a nodule or mass in hilar region. Literature search has shown very few cases of immunohistochemically confirmed cases of pulmonary plasmacytoma. Diffuse pulmonary infiltration is an unusual presentation. Case presentation We report the case of a 56 year old lady with history of cough and breathlessness since one month. Computed Tomography revealed diffusely scattered multiple cavitating nodules and consolidation in both lungs. Computed Tomography guided biopsy of one of the lung nodules was done. Histopathologic examination and immunohistochemistry showed features of pulmonary plasmacytoma .This is an unique case of primary pulmonary plasmacytoma with the rare presentation as diffusely scattered multiple cavitating nodules and consolidation. According to our literature search, primary pulmonary plasmacytoma manifesting as cavitating nodules is being reported for the first time. Conclusions Primary pulmonary plasmacytoma should be also be considered in the differential diagnosis of multiple diffusely scattered cavitating lung nodules.