1. A case of solitary plasmocytoma of the thoracic part of the spine, verified by necropsy, is described.

2. A brief review is given of eighteen acceptable cases of solitary plasmocytoma of bone.

3. Of the eighteen patients, fifteen were men; the five spinal tumours were all in men.

4. Diagnosis requires: a) biopsy identification of plasmocytoma; b) exclusion of the possibility of generalised myelomatosis by complete radiography of the skeleton, repeated if necessary at intervals during the ensuing two or three years or longer.

5. A tumour of brief duration, proved to be solitary by careful necropsy, cannot be placed with certainty in the group of truly solitary plasmocytomas; it might have been a precocious first lesion of myelomatosis.