A 35-year-old woman underwent chest radiography 2 years previously, which indicated an abnormal shadow in the left hilum. Moreover, a round tumor with a smooth surface was detected in the left upper lobe of the lung by computed tomography. The tumor gradually increased in size over 2 years, and positron emission tomography showed abnormal uptake by the tumor. Although multiple smooth surface tumors were detected in the ileocecal region adjacent to the uterus and in the greatest gluteal muscle, video-assisted thoracoscopic surgery (VATS) was performed to remove the intrathoracic tumor for differential diagnosis. Histological examination revealed fasciculated spindle-shaped cells that were positive for S-100 and vimentin. Considering the patient's family history, a diagnosis of familial schwannomatosis with intrapulmonary schwannoma was made. In the present case, although the tumor appeared to be benign, an appropriate approach such as VATS was required for definite diagnosis and complete therapy when the tumor had grown in size.