Uterine inflammatory myofibroblastic tumor: First report of a ROS1 fusion

• DOI: 10.1002/gcc.22986
• Publication Date: 2021-07-29T09:01:27Z
• Authors: Jennifer A. Bennett; Peng Wang; Pankhuri Wanjari; Lidia Diaz; Esther Oliva
• Keywords: Neoplasm

Inflammatory myofibroblastic tumor (IMT) of the uterus is an uncommon mesenchymal neoplasm that frequently harbors ALK rearrangements. In this report, we describe first uterine IMT with a FN1-ROS1 fusion, which occurred in 43-year-old woman who presented menorrhagia. Morphologically, well-circumscribed 3 cm was comprised compact and myxoid foci relatively bland spindle cells admixed scattered chronic inflammatory limited to areas. ROS1 showed moderate cytoplasmic granular staining < 30% foci, while negative. RNA sequencing detected rearrangement fused FN1 exon 37 34. Although non-ALK-rearranged IMTs are exceedingly rare, example highlights importance performing immunohistochemistry and/or molecular analysis ALK-negative neoplasms morphologically compatible IMT.