A 74-year-old woman was admitted to our hospital because of abnormal shadow on a chest X-ray. Chest CT revealed a 30-mm tumor in the left lingular segment, and PET/CT indicated abnormal FDG accumulation (SUV_max: 10.37) in this nodule. The tumor could not be diagnosed via bronchoscopic examination. A video-assisted thoracic surgery was performed for definitive diagnosis and treatment. The tumor presented an extrapulmonary, smooth surface and a mushroomed-shaped tumor. A partial lung resection was performed, and a frozen section revealed the proliferation of stromal tissue with no malignant cells. Ultimately, the tumor was diagnosed as an inflammatory myofibroblastic tumor from the results of anaplastic lymphoma kinase (ALK) positive and other immunochemical examinations. Pulmonary inflammatory myofibroblastic tumors (PIMTs) are rare and difficult to distinguish from malignant tumors.