Conclusions:
MTEM is a rare neoplasm that is associated with radiation therapy, especially with a long latency period after initial exposure.10 They are histologically and immunohistochemically identical to mammary myofibroblastoma. Radiation-induced neoplasms are rare, but potentially life-threatening complications of radiotherapy generally requiring aggressive surgery. This case illustrates successful diagnosis and treatment of a radiation-induced MTEM in a patient with a history of retinoblastoma treated by external beam radiation. The neoplasm was removed with negative margins via partial maxillectomy and total ethmoidectomy without perioperative complications or local recurrence to date.