There is no doubt that occasionally there occurs in a bone containing active marrow, a malignant clone of plasma cells that grows as a single tumour and causes bone destruction such that the patient comes to clinical attention with bone pain and an x-ray shows destruction within the bone; on further staging (vide infra) there is no sign of any other disease elsewhere in the body.
Such a single bone lesion is known as a solitary plasmacytoma and is treated as a solitary tumour – see below. However, there is no doubt that such single plasmacytomas seed off cells of their origin and that when these take hold and grow in the other bones of the body and permeate the marrow then the disease is called multiple myeloma. Solitary plasmacytoma may therefore be said to give rise to myeloma.
Exposure to ionising radiation also predisposes to myeloma and the Japanese nuclear weapon survivors have an increased incidence of this disease, as did the early generations of radiologists.
