THE SIGNIFICANCE OF SINONASAL RADIODENSITIES - OSSIFICATION, CALCIFICATION, OR RESIDUAL BONE

PURPOSE: To determine whether very radiodense material within a sinona sal soft-tissue mass on CT can be differentiated as calcification, oss ification, or residual bone. METHODS: We retrospectively described the radiodensities within 235 sinonasal soft-tissue masses as discrete, s olitary or multiple, or as a diffuse process with either a well-define d or poorly defined margin. They were also classified as calcification , ossification, or residual bone. Findings were correlated with pathol ogic specimens. RESULTS: Residual bone was underdiagnosed; calcificati on was overdiagnosed. A solitary discrete density was most likely to b e calcification within an inflammatory mass. However, multiple discret e densities were as likely to be in a tumor as in an inflammatory lesi on. If the process was diffuse with a well-defined margin, it was most likely to be a benign fibroosseous lesion. If the process was diffuse with a poorly defined margin, it was most likely to be a high-grade s arcoma. Densities within inverted papillomas were shown to be residual bone, not calcifications; densities within esthesioneuroblastomas wer e calcifications. CONCLUSION: Radiodensities may help in refining a CT diagnosis, but one may not know based on CT whether the density is a calcification, ossification, or residual bone.