Inflammatory myofibroblastic tumor mimicking lymphoma on 18F-FDG PET/CT. Report of a case and review of the literature.

Inflammatory myofibroblastic tumor (IMT) is an uncommon neoplasm that has been described in various locations throughout the body, but is rarely observed in systemic lymph nodes. We present a case of a 63 years old woman with left inguinal lymphadenopathy accompanied by low-grade fever. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) revealed abnormal higher 18F-FDG uptake on the neck, axillar, pulmonary hilar, mediastinal, mesenteric, retroperitoneal, pelvic and inguinal lymph nodes. These findings led to an initial misdiagnosis of lymphoma. Final histological diagnosis revealed an IMT. The patient was treated with oral steroids. Ultrasound assessments showed a complete resolution of systemic enlarged lymph nodes at the end of 1 month of therapy. There has been no evidence of recurrence through 12 months of post-treatment monitoring. This case suggests that IMT should be considered as a possible differential diagnosis in apparent cases of lymphoma. Further, it indicates that steroid therapy may serve as an effective treatment for IMTs that systemically affect lymph nodes.