Schwannomas are typically solitary lesions in deep or superficial soft tissues, usually occurring along the nerves of the head, neck, and upper and lower extremities. In the thoracic cavity, schwannomas are most frequently located in the posterior section of the mediastinum, arising from the sympathetic trunk or intercostal nerves. In soft tissue tumors, with the exception of lipomas, hemangiomas, and desmoid tumors, tumors larger than 5 cm are more likely to be malignant. Usually, schwannomas are small masses (< 5–6 cm), but several intrathoracic giant schwannomas have been reported. [2,3,4,5,6,7,8]. The specific mechanisms associated with enlargement of Schwannoma are not yet fully elucidated, but mutations in the NF2 gene and abnormalities in signaling pathways have been suggested [9]. When the tumor becomes large, it causes symptoms due to pressure on the surrounding tissues, but, no reports of cases of tumor-related death associated with benign intrathoracic schwannoma. This case appears to be a rare and valuable instance where a benign tumor inexplicably grew significantly over a period of 10 years, leading to death due to reasons such as missed surgical timing resulting from the lack of follow-up and the presence of comorbid psychiatric illness.

Resection of giant tumors is challenging because of their enormous size and serious adhesion to surrounding organs. It may be necessary to perform a combined resection of adherent tissue. The main challenge is how to control the amount of bleeding. When the tumor is huge and a poor surgical exposure is presupposed then, piecemeal removal is the only choice because an en-block resection is impossible. One strategy to reduce bleeding is preoperative embolization [10], which we also planned to do this case.

There is currently no effective drug therapy for schwannomas. Neurofibromatosis type 2 (NF2) involves multiple schwannomas and meningiomas in the cranial and spinal nerves. Acoustic schwannomas can grow to a critical size, compress the brainstem, and may lead to death. Resection is not always easy; therefore, several therapeutic agents have been considered. Sagers et al. reported that the combination of an mTOR inhibitor and dasatinib may be effective for the treatment of vestibular schwannomas [11]. In addition, a report on the efficacy of the vascular endothelial growth factor (VEGF) receptor vaccine for NF2 [12] and a multicenter, double-blind, randomized, controlled trial investigating the efficacy and safety of bevacizumab are ongoing.

In conclusion, generally, schwannomas are benign and asymptomatic; we therefore sometimes do not pay much attention to them. However, in some cases, tumors gradually become larger and seriously compress the neighboring mediastinal organs, leading to death.

Therefore, a benign tumor should not be neglected, and if surgery is not possible at the time of diagnosis, a regular follow up is necessary, in order not to miss the right timing for surgery.