We report a case of peripheral T-cell lymphoma that was initially found to have the aberrant karyotype 47,XX,t(2;13)(q22;q22),+19. At relapse 2 years later, a malignant clone with the karyotype 46,XX,der(22)t(2;22)(q31;q13) was identified. This rearrangement leads to a duplication of the distal part of the long arm of chromosome 2. We used chromosome-specific painting libraries and multicolor fluorescence in situ hybridization, as a complement to banding analysis, to resolve the karyotype.