Inflammatory Myofibroblastic Tumor (IMT)

Overview

Inflammatory myofibroblastic tumor (IMT) is a distinctive mesenchymal neoplasm of intermediate biological potential (locally aggressive, rarely metastatic) composed of myofibroblastic spindle cells with a prominent inflammatory infiltrate. It predominantly occurs in children and young adults. IMT is defined by recurrent kinase gene fusions (most commonly ALK in ~50%, but also ROS1, RET, NTRK, PDGFR, and JAK fusions). The discovery of targetable kinase fusions has transformed treatment of unresectable IMT.

Cohorts in the corpus

  • mixed_pipseq_2017 — PIPseq pediatric pan-cancer cohort (Columbia University Medical Center), which includes an IMT case among 101 high-risk pediatric patients PMID:28007021.

Recurrent alterations

  • PIPseq cohort: VCAN-IL23R fusion identified by RNA-seq in an IMT patient — a JAK-inhibitor target; the patient received matched targeted therapy (JAK inhibitor) PMID:28007021.

Subtypes

  • ALK-positive IMT (~50%): most common; crizotinib highly active.
  • ALK-negative IMT: may harbor ROS1, RET, NTRK, PDGFR, or JAK fusions (as in PIPseq VCAN-IL23R case); each requires matched TKI selection.

Therapeutic landscape

  • Surgical resection for localized disease; for unresectable/metastatic disease, kinase inhibitors directed by fusion partner: ALK — crizotinib (high response rate); ROS1 — crizotinib; JAK-pathway fusions — JAK inhibitors; NTRK — larotrectinib/entrectinib PMID:28007021.

Sources

  • PMID:28007021 — Oberg et al. PIPseq pediatric pan-cancer sequencing program (n=101).

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