Radiation induced malignancy in retinoblastoma: new pathology in a case report.

OBJECTIVE Patients with a genetic history of retinoblastoma have an increased risk of developing a second neoplasm. When these secondary malignancies occur in the previously irradiated field of the primary tumor they are most commonly osteosarcomas, fibrosarcomas, and squamous cell carcinomas. We present the first case of a radiation induced adenocarcinoma in a patient after treatment for retinoblastoma. STUDY DESIGN A case report of one patient. METHODS This case study underwent a chart review, comprehensive history, physical exam, rigid nasal endoscopy, and radiographic imaging. A literature review of the MEDLINE database 1966-2009 using key words, retinoblastoma, radiation, and second malignancy was performed. RESULTS Our case is a 29 year old man with a past medical history significant for surgical resection followed by irradiation at age 1 for retinoblastoma who presented with right sided epistaxis and nasal obstruction. Endoscopy revealed a mass in the right nasal cavity. MRI and CT revealed a mass filling the right nasal cavity and ethmoids with erosion through the cribriform plate. The patient underwent surgical resection and pathology revealed an adenocarcinoma. CONCLUSIONS Second malignancies in patients with retinoblastoma tend to occur in the previously irradiated field of the primary tumour and contribute significantly to long term morbidity and mortality rates. This is the first case of a sinonasal adenocarcinoma occurring in the previously irradiated field. The endoscopic skull base surgeon plays a vital role as patient survival depends on the diagnosis and surgical management.