Inflammatory myofibroblastic tumor of the neck with thyroid invasion: a case report and literature review

Inflammatory myofibroblast tumor (IMT) is a unique intermediate soft tissue tumor, comprising myofibroblasts/fibroblasts, with infiltrating plasma cells, lymphocytes, and/or eosinophils. IMT, first reported in 1939 in the lung or pleura, is most common in children or adolescents and in the lungs; however, it can also occur in other tissues. The exact etiology and pathogenesis of IMT are yet to be clarified. Virus-induced trauma, surgery, autoimmune etiology, inflammation, infection, and abnormal responses to long-standing exogenous stimuli in the body, dominated by myofibroblast proliferation, can lead to IMT development. Most patients with IMT have masses, with or without physical manifestations, including fever, weight loss, and various clinical laboratory abnormalities. Surgical resection is the main treatment. IMT is not common in the head and neck region, and additional thyroid involvement is rare. A male patient presented a rapidly growing neck mass was treated and diagnosed with IMT in the neck and thyroid involvement in our hospital in September 2018 by successful surgical resection. Follow-up for 6 months showed no recurrence or metastasis. We review the etiology, clinical features, pathological features, treatment, and prognosis of IMT, with the aim of improving the diagnosis and treatment of this condition in the head and neck region.