A Solitary plasmacytoma of bone(SPB) is a rare disease. This paper reports a case of SPB with massive aggregation of histiocytes known as pseudo-Gaucher cells. A 40-year-old male presented with progressive paraparesis and paraesthesia. The Magnetic Resornance Image(MRI) revealed a tumor mass in the thoracic spine that occupied the three colum. The tumor invaded the epidural space of T6 vertebra with compression of the spinal cord. There were no laboratory abnormalities. It was gross totally resected and his neurological symptoms improved. The microscopic examination revealed a plasmacytoma with massive aggregation of histiocytes. Futher neuroradiological studies were carried out and no other lesions were detected.