A malignant inflammatory myofibroblastic tumor of the hypopharynx harboring the 3a/b variants of the fusion gene.

Inflammatory myofibroblastic tumors (IMT) in the head and neck region are rare neoplasms that generally mimic benign/low-grade neoplasms. Overexpression of anaplastic lymphoma kinase () has been reported in 50% of IMT cases, secondary to activation by structural rearrangements in the gene, which results in a fusion protein with echinoderm microtubule associated protein like 4 () in ~20% of cases. The present study describes a case of a 74-year-old woman with a malignant IMT in the right posterior hypopharynx harboring a previously unreported chromosomal rearrangement resulting in and gene fusion. Strong ALK immunoreactivity was observed in neoplastic cells, while fluorescent hybridization combined with fluorescent fragment analysis and direct sequencing identified the first case of the 3a/b variants of the fusion gene in IMT. The results of the current study highlight the uncommon occurrence of ALK-positive IMT in the head/neck region and demonstrate the importance of integrating different molecular methodologies to identify unequivocal gene fusion characterization.