Mediastinal epithelioid inflammatory myofibroblastic sarcoma with the EML4-ALK fusion: A case report and literature review.

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of inflammatory myofibroblastic tumour which rarely affects the chest cavity. We, for the first time, report a case of mediastinal EIMS with the EML4-ALK fusion. A young woman presented to our hospital with cough, chest tightness and shortness of breath. Computed tomography (CT) showed a mixed attenuation soft-tissue mass in the right middle and upper mediastinum. Negative results were obtained from bronchoscopy forceps biopsy and endobronchial ultrasound-guided transbronchial fine needle aspiration. CT-guided percutaneous biopsy was finally performed. However, due to the rapidly progressed EIMS that compressed the trachea and right main bronchus, the patient died of respiratory failure 1 day before diagnosis. EIMS progresses rapidly, and an early diagnosis is important. For mediastinal EIMS, CT-guided percutaneous biopsy may be useful. Next-generation sequencing of blood may be instructive to EIMS patients who are intolerant to invasive biopsy.