Traumatic tumor hemorrhage of inflammatory myofibroblastic tumor of the lung.

A 23-year-old female with a history of idiopathic epilepsy was found to have a right chest cavity shadow in a school health checkup 5 years before. CT revealed a thin-walled cavity lesion in the right middle lobe containing a ball-like mass, showing air crescent sign. After falling due to a seizure, she was transported by ambulance and admitted. CT revealed diffuse ground-glass opacities throughout the right lung field. Bronchoscopy revealed bloody bronchial alveolar lavage fluid. Due to the tumor hemorrhage, an elective simple right middle lobe resection was performed without complications. The initial immunohistochemical staining was negative for ALK using ALK1 clone; however, subsequent staining of ALK by D5F3 and 5A4 clone was positive. Immunostaining findings led to a diagnosis of inflammatory myofibroblastic tumor. The patient remains under regular observation and has experienced no recurrence over the 6-year postoperative period. This case contains two different points: the first is that a cavity lesion of inflammatory myofibroblastic tumor may cause traumatic bleeding and should be treated with caution; the second is that attention should be paid to differences in stainability among clones when diagnosing inflammatory myofibroblastic tumor.