Castleman disease is a rare disease entity of unknown etiology, with the characteristics of large, well marginated benign lymphoid masses occuring predominently in the mediastinum. The value of contrast enhancement in solid soft tissue masses of mediastinum has little been written because most of the solid mediastinal tumors show no significant degree of enhancement. But Castleman disease, because of its hypervacularity, show significant degree of enhancement in most cases. Authors report 3 cases of Castleman diseases and suggests good diagnostic probability of CAstleman disease in cases that show benign looking homogeneously enhancing mediastinal mass by CT scan.