Schwannoma is more prone to focal bleeding, necrosis, and cystic degeneration, and the nearby nerves at both ends show a specific manifestation of “rat tail sign” on ultrasonography for identification.[14] Leiomyomas are more common in middle-aged and elderly patients, arise in the pelvis, retroperitoneal and abdominal cavity.[15] The morphology under the microscope is similar to that of IMT, however immunohistochemical expression of myogenic antibodies such as SMA is positive, and negative ALK can be distinguished from IMT. The gene discussed is SMN1; the disease is inflammatory myofibroblastic tumor.