[en] A patient with type AB thymoma and del(6)(p22p25) as the sole cytogenetic anomaly is described. This is the second report of a del(6)(p22p25) in a thymoma. The same deletion was previously found in association with a type A thymoma. Both patients presented with benign tumors. These data suggest that partial deletion of the short arm of chromosome 6 is a nonrandom change associated with benign thymomas. (C) 2003 Elsevier Inc. All rights reserved.