A malignant tumour of plasma cells, usually found in lymph nodes or bone marrow.
Neoplasm of plasma cells, occurring in bone marrow usually in association with multiple myeloma, or, less commonly, occurring in soft tissues, especially those of the upper respiratory tract.
A malignant tumor of plasma cells, very closely allied to myeloma. It usually occurs as a solitary tumor of bone, but may be multiple. Less frequently it affects soft tissues, usually the upper air passages. All of these tumors may produce the abnormal gamma globulins that are characteristic of myeloma, and they may progress to widespread myeloma. The soft tissue tumors often respond to radiotherapy and to such drugs as melphalan and cyclophosphamide; the bone tumors are less responsive. Tumors originating in soft tissue may spread to bone, producing an appearance on X-ray identical to myeloma deposits; these secondary growths often resolve completely after radiological treatment.