[Multiple extra-bone sites of Kahler's disease]

The authors report the case of an IgA secreting multiple myeloma which, after a rapid initial remission, relapsed with skin, thyroid, testis and lung metastases without bone recurrence. A review of the medical literature on this subject underlines the poorly differentiated microscopic appearance and the low secretion of paraprotein of these extraosseous plasmacytic tumours which have a poor prognosis due to their increased malignancy.