A hole in the skull: CT manifestations of a solitary plasmacytoma in skull.

Plasmacytoma can present as multiple myeloma, solitary plasmacytoma of the bone (SPB), or extramedullary plasmacytoma. SPB is a rare entity that composes of malignant plasma cells and involves the bone to form only one or two lesions without evidence of disease dissemination. It accounts for only 4% of malignant plasma cell tumors. We report a case of SPB in the skull in a 59-year-old male. CT scan revealed an 8 cm ×9 cm osteolytic lesion on the scalp of skull with a well demarcated margin. A cake-like mass was revealed at CT soft tissue window. The mass was completely excised and histological examination revealed plasmacytoma. The diagnosis of SPB was established after ruling out multiple myeloma.