Solitary plasmacytoma is a rare malignant neoplasm that originate in immunoglobulin-producing plasma cell. Solitary bone plasmacytoma can be found at any site throughout the skeleton and in most cases eventually progresses to multiple myeloma, of which it is thought to be an unusual presentation. On the other hand, extramedullary plasmacytoma has a tendency to occur in the head and neck region, mainly in association with the upper air passages. Incisional biopsy is the primary approach to make a definitive diagnosis, and immunohistochemical staining can be very helpful in understanding the nature of these tumors. We report a 66 years old patient with solitary bone plasmacytoma and a 36 years old patient with solitary extramedullary plasmacytoma with literatures review.