We present the MR imaging features in two cases of mediastinal Castlem
an's disease of the hyaline-vascular type. T1-weighted MR images showe
d rounded hilar masses of intermediate or high signal intensity with a
reas of low signal due to vessels and calcification. On T2-weighted im
ages, the masses were of high signal intensity. Mediastinal masses wit
h the above signal characteristics and vascular signal voids may sugge
st a diagnosis of Castleman's disease.