Partial response to chemotherapy in a patient with retroperitoneal inflammatory myofibroblastic tumor

Retroperitoneal inflammatory myofibroblastic tumor (IMT) is a rare lesion of unknown etiology. The management of IMT may be challenging due to its intermediate malignant potential, the possibility of local recurrence after surgical resection and its unique anatomic location, which makes radical resection impossible due to its proximity to vital structures. Thus, treatment for recurrence and metastasis mainly relies on chemotherapy. We herein report a case of a 60-year-old man with an IMT sized 6.7×5.1 cm, located in the left adrenal area, which was identified by a computed tomography (CT) scan of the abdomen. Radical surgical resection of the tumor was not feasible, as it was fixed to the left renal artery. After 5 months, the patient underwent CT-guided radiofrequency ablation of the re-growing tumor. An unresectable mass was detected in the patient's rectum by a CT scan of the pelvis. Subsequently, the patient underwent chemotherapy for the recurring and metastatic tumors. The chemotherapeutic regimens included epirubicin, dacarbazine and docetaxel. Over the last 6 months, after three cycles of therapy, the sizes of the primary and metastatic tumors had decreased on the follow-up CT scan. Thus, chemotherapy effectively controlled the disease in this case, following unsuccessful surgical resection and radiofrequency ablation. The present case report highlights the complexity of treatment in such cases and the significance of designing a clinical protocol for the treatment of IMT.