CT-pathologic correlation in a case of solitary plasmacytoma of the rib

We report a case of solitary plasmacytoma of rib origin in a 46-year-old man. CT revealed a focal expanding mass in the right fifth rib. The mass showed ridging, cortical thickening, and fine erosion on the inner aspect of the cortex and had partly penetrated the bone. On both T1- and T2-weighted MR images, the mass showed low to intermediate intensity, and contrast studies showed homogeneous enhancement. Whole body bone scintigraphy revealed abnormal solitary accumulation, and therefore surgical resection was performed. Macroscopically the specimen revealed destruction of the cortex caused by tumor invasion, corresponding to the CT findings. Microscopic findings included a large number of plasma cells, leading to a histopathological diagnosis of plasmacytoma.