The common diagnostic possibilities when a mediastinal or hilar mass is discovered in the absence of parenchymal pulmonary disease can be divided into diseases of mediastinal structures and diseases of lymph nodes. The former group includes benign cysts, dermoid cysts, teratomas, tumors of the thyroid and thymus, and tumors of neural origin and of connective tissue.1 The common causes of hilar or mediastinal lymph node enlargement are granulomas, lymphomas, and metastatic carcinoma, while reactive hyperplasia, erythema nodosum, sarcoidosis, and leukemia virtually comprise the less common causes. Plasma-cell tumors of the hilar nodes are unusual members of this latter group. The discovery of a plasma-cell tumor in a large hilar node of an asymptomatic 47-year-old man provoked this review of the life history and significance of extramedullary plasma-cell tumors located within the chest, and particularly of their relationship to multiple myeloma. Report of Case A 47-year-old white laborer was admitted