INFLAMMATORY MYOFIBROBLASTIC TUMOR OF THE MEDIASTINUM: A RARE CASE REPORT

Abstract

TOPIC: Disorders of the Mediastinum TYPE: Medical Student/Resident Case Reports INTRODUCTION: Inflammatory fibroblastic tumors (IMT) are rare. It is most common in children and adolescent. The most common sites are lung, liver, spleen, head and neck and very rarely mediastinum. We present a patient who was diagnosed with rare IMT of the mediastinum (IMTM). CASE PRESENTATION: A white female in her late twenties with history of substance abuse presented with progressive dysphagia, odynophagia and weight loss since last 1 month with exertional shortness of breath. Physical examination showed cachectic female with tenderness to palpation of the neck and intravenous track marks on both upper extremities with normal saturation on room air. Computed tomography (CT) of the neck revealed 3 x 3.5 cm right paratracheal mass and therefore she underwent CT of the chest which revealed 10 x 9.4 cm mass in the right para-hilar area invading the mediastinum resulting in obstruction of the esophagus and right main bronchus along with compression of inferior aspect of the trachea. There was also an encasement of right pulmonary artery and right side of the atrium. Bronchoscopy with biopsy was performed, which remained non-diagnostic. Patient underwent endoscopic bronchial ultrasound with biopsy but again remained to be non-diagnostic. Our patient was considered as a high risk for a thoracoscopy procedure under general anesthesia for tumor resection due to her airway and vascular compromise along with risk of aspiration due to esophageal obstruction. Therefore, she underwent with CT guided biopsy of the mediastinal mass which revealed inflammatory cells with atypical appearing spindle cells confirming the diagnosis of IMTM with TFG-ROS1 gene fusion. She was discharged home with gastrostomy tube for nutrition and was started on crizotinib by oncologist. After five months, her tumor size shrink to 7.5 x 7.2 cm. She is currently tolerating soft diet and continued to be on crizotinib neo-adjunctively with plan for surgical resection in the future. DISCUSSION: IMTM are discovered on imaging when patient presents with symptoms including dyspnea, cough, thoracic discomfort and dysphagia. Establishing diagnosis of IMT on needle biopsy is difficult due to small tissue sample. Only 6.3% of IMT cases are diagnosed on analysis of biopsy specimen alone. Definitive diagnosis requires histopathologic and immunohistochemical study from a resected tumor. IMT most commonly have ALK gene rearrangements. Recently, kinase fusions including ROS1 and PDGFRβ are also identified. Surgical resection is considered as a definitive treatment, but, crizotinib, a new chemotherapeutic agent is being used recently, with improvement in the tumor burden which are not amenable to resection. CONCLUSIONS: In conclusion, we are reporting a rare IMT occurring in mediastinum which rarely presents with dysphagia and need to be included as differential diagnosis in young patients presenting with obstructive dysphagia. REFERENCE #1: Gorolay V, Jones B. Inflammatory myofibroblastic tumor of mediastinum with esophageal and bronchial invasion: a case report and literature review. Clin Imaging. 2017 May-Jun;43:32-35. doi: 10.1016/j.clinimag.2016.09.012. Epub 2016 Sep 28. PMID: 28178581 REFERENCE #2: Khalil, Sumaira, Ghafoor, Tariq, Raja, Amna Kaneez Fatima. Inflammatory Myofibroblastic Tumor: A Rare Presentation and an Effective Treatment with Crizotinib. (2020) Case Reports in Oncological Medicine REFERENCE #3: Mai S, Xiong G, Diao D, Wang W, Zhou Y, Cai R. Case report: Crizotinib is effective in a patient with ROS1-rearranged pulmonary inflammatory myofibroblastic tumor. Lung Cancer. 2019 Feb;128:101-104. doi: 10.1016/j.lungcan.2018.12.016. Epub 2018 Dec 17. PMID: 30642440 DISCLOSURES: No relevant relationships by Raguraj Chandradevan, source=Web Response No relevant relationships by Arish Maknojia, source=Web Response No relevant relationships by Taniya Mathew, source=Web Response No relevant relationships by Neeta Sukthanker, source=Web Response