Solitary plasmacytoma of the skull: a case report.

Solitary plasmacytoma of the skull is very rare and only 35 cases have been reported in the English literature. It remains controversial whether solitary plasmacytoma of the skull is essentially identical with solitary plasmacytoma of bone or not. Solitary plasmacytoma of bone including solitary plasmacytoma of the skull is characterized by a radiologically solitary bone lesion, neoplastic plasma cells in the biopsy specimen, fewer than 5% plasma cells in bone marrow, less than 2.0 g/dl monoclonal protein in the serum when present and negative urine test for Bence Jones protein (monoclonal light chain). Solitary plasmacytoma of bone tends to disseminate or progress to multiple myeloma even as long as 7-23 years after presentation. We report the first case of solitary plasmacytoma of the skull in which both beta2-microglobulin for detection of early renal disturbance and neoplastic plasma cell labeling index for detection of DNA synthesis were examined in order to predict the clinical course of solitary plasmacytoma of the skull.