FISH demonstrates

ALK rearrangement, t(2;19), and der(5)t(5p;19q).(A) ALK split-apart FISH probe shows normal fused orange/green signal on normal No. 2 homologue, and split green signal on der(2) and orange signal on der(19). (B) Same metaphase rehybridized with 19p subtelomeric sequences, showing translocation of 19ptel to der(2). (C) FISH with dual-color whole chromosome paint probes shows No. 19 sequences (orange) translocated to der(2) and der(5) and No. 2 sequences (green) on der(19). (D) Subtelomeric sequences for 5p (green) and 19q (orange) show retention of 5ptel on der(5), and 19qtel translocated distal to 5ptel.