Two pulmonary plasmacytomas of different immunologic type, occurring with an interval of 5 years in the same 65‐year‐old woman are reported. Both displayed identical light chain types, but different heavy chains. The immunoperoxidase staining technique was used. The patient underwent segntental resection, and no evidence of recurrence or multiple myeloma was found 4 years later. Differential diagnoses are discussed, and the importance of immunologic staining is stressed.