Cytomorphology and Immunohistochemistry of Inflammatory Myofibroblastic Tumor: A Diagnostic Challenge

Background and Aim: The Inflammatory myofibroblastic tumor (IMT) is a tumor of intermediate grade with a low rate of metastasis. It often presents in paediatric age group and young adults. There is very sparse literature available which describes the cytological findings of this rare lesion. Here, we have reviewed cytologically described findings of inflammatory myofibroblastic tumor. Material and Methods: We explored the published literature from all geographical global locations, including articles from the earliest date of publication and carried out an independent, till date, systematic digital search for studies via PubMed, Google, and Google scholar. Search keywords were: Inflammatory myofibroblastic tumor, Inflammatory pseudotumor, Lung, Case report, case series, FNAC, cytology. We did comprehensive review of the reported cases of IMT till date which essentially described cytological features of the aspirate. Only the cases confirmed with histology and supported by immunohistochemistry (IHC) were included. Results: Majority of the lesions were located in lungs. The most frequent cytological findings in IMT are marked cellularity with mild cytological atypia, predominant population of myofibroblasts and variable inflammatory cell population. The most common positive markers in IMT is Smooth Muscle Actin (SMA). Conclusion: The consistent cytological findings found were spindle cell population associated with inflammatory cells. The variable appearance on radiology and rarity of this tumor are few of the factors which often result into a biased diagnosis. This article guides a pathologist for cytodiagnostic pointers of IMT and diagnostic traps often hindering a correct, confident diagnosis of IMT on cytomorphology.