ALK-ATIC fusion in urinary bladder inflammatory myofibroblastic tumor

Abstract

In this report, we describe an inflammatory myofibroblastic tumor (IMT) of the urinary bladder in a 46-year-old man. Tumor cells presented striking cytoplasmatic ALK immunopositivity. Cytogenetic and FISH analysis, by use of a multicolor chromosome 2 banding probe, revealed a 46,XY,der(2)(2pter-->2p23:2q35-->2q37:2p11-->2q35:2p23-->2p11:2q37-->2qter) karyotype. Subsequent FISH and RT-PCR analysis confirmed the ALK-ATIC chimeric fusion in tumor cells. This is the first evidence of a variant rearrangement involving the ATIC gene in IMT and the first cytogenetic description of an IMT originating from the urinary bladder.