Uterine inflammatory myofibroblastic tumour: A case report

Abstract

Inflammatory myofibroblastic tumour (IMT) is a mesenchymal neoplasm with intermediate biological potential, which may be under-recognised in the uterus.1–3 Morphological and immunophenotypic overlap exists between uterine IMT and some other uterine mesenchymal neoplasms, including smooth muscle tumours.2 Morphological features suggestive of IMT may be subtle or focal and include myxoid change, tapered nuclei, and a lymphoplasmacytic infiltrate.1 Chromosomal rearrangements involving the anaplastic lymphoma kinase (ALK) gene appear to be frequent in uterine IMT,1–3 and absent in other uterine mesenchymal neoplasms.2 Therefore, ALK immunohistochemistry (IHC) and ALK florescent in situ hybridisation (FISH) appear to be useful tools to confirm the diagnosis of uterine IMT.3 Although most uterine IMTs follow a benign clinical course, local recurrence and metastases have been observed in a small subset.1 Correct diagnosis is important to ensure accurate prognosis and optimal management, which may include a tyrosine kinase inhibitor. We present a case of uterine IMT with morphology and IHC suggestive of a leiomyosarcoma with myxoid change. ALK IHC was positive and an ALK rearrangement was demonstrated with FISH, confirming the diagnosis of uterine IMT. This case illustrates the importance of a low threshold for ALK testing in uterine mesenchymal tumours with morphological features suggestive of IMT.