Extrapulmonary inflammatory myofibroblastic tumor at different sites with histopathology and immunohistochemical analysis: A case series

Background: Inflammatory myofibroblastic tumor (IMT) is a rare entity and has wide anatomical sites of origin. Because of overlapping clinical and radiological features, histopathology study followed by immunohistochemistry (IHC) analysis is necessary for confirmation of the diagnosis. Aim of the Study: This study aimed to present the demographic, histopathological, and IHC analysis of patients diagnosed with extrapulmonary IMT. Materials and Methods: Patients diagnosed with extrapulmonary IMT were analyzed from January 2017 to July 2018. Results: A total of six cases were included in our series, with the mean age of presentation being 37 years. Male-to-female ratio was 1:2. The primary site of origin was distributed as follows: two cases of face and neck (one mandible and one naso-orbital), three cases of abdominal location (one spleen, one periaortic node, and one paraaortic node), and one case of cervix. There was no local invasion or metastasis found. Microscopically, all the cases revealed a common pattern of finding of the presence of intersecting fascicles of spindle cells with intervening collagenous to myxoid matrix along with infiltration of plasma cells and aggregates of lymphocytes. There were no atypical cells or mitosis in all the cases. All six cases were smooth muscle actin and vimentin positive and S100, desmin, and cytokeratin negative on IHC study. All the cases were anaplastic lymphoma kinase (ALK) negative, except one case with cervical primary where it was positive for ALK-1. Conclusion: Extrapulmonary IMT is a rare entity with diagnosis by exclusion on histopathological examination, and IHC should be done for confirmation of the diagnosis as well as ALK expression status.