MRI of radiation-induced tumors of the head and neck in post-radiation nasopharyngeal carcinoma

Abstract

The aim of this study was to document the sites and MRI features of radiation-induced tumors (RITs) in the head and neck following treatment for nasopharyngeal carcinoma (NPC). The MRI examinations and clinical records of 20 patients with 21 RITs were reviewed retrospectively. RITs developed 3-30 years after radiotherapy and included eleven squamous cell carcinomas, six sarcomas, two neuroendocrine carcinomas, one mucoepidermoid carcinoma and one meningioma. RITs arose in the maxillary region (9), oro/hypopharynx and oral cavity (5), external auditory canal (4), nasopharynx and sphenoid sinus (2) and brain (1). Radiation-induced carcinoma and sarcoma had MRI features that were useful to distinguish them from recurrent NPC. To improve early detection of RITs, the check areas on an MRI of a patient with previous NPC treated by radiation should always include the maxillary region, tongue, and external auditory canal/temporal bone.

Radiation-Induced Maxillary Osteosarcoma and Synchronous Oropharyngeal Squamous Cell Cancer: A Rare Case Report

“…Differential diagnosis of radiation induced sarcoma from SCC may be difficult. A wide range of histologic subtypes of sarcomas cause variable signal characteristics, heterogeneity and more contrast enhancement on MRI when they are compared with the SCC or recurrent NPC [9]. In our patient the osseous matrix of the large tumor with the soft tissue component extending to the nasal cavity can easily be detected by both CT and MRI.…”

“…Therefore malign tumors of these regions can arise after radiation therapy as one of the late complications. The latent period following radiation therapy for nasopharyngeal carcinoma and the development of secondary tumors was 5-30 years with a mean of 12.9 years [3,9]. Our patient developed the secondary tumors 10 years after primary radiation therapy.…”

“…go, et al [9] investigated 884 patients with previously treated NPC retrospectively and reviewed 21 radiation induced tumors. They found that 11 of the patients developed squamous cell carcinomas in the radiated field and 6 of the patients developed sarcomas in the radiated field.…”

“…Histological examination of oropharyngeal soft tissue mass showed lobules, thick basement membrane, cribriform small basaloid cells with peripheral palisading, cells with minimal cytoplasm and moderately pleo- Abrigo [9] emphasized that radiation induced sarcomas were large with extension of soft tissues at the time of MRI examination because of the aggressive characteristics of these tumors. Radiation-induced changes such as osteoradionecrosis and pathologic fracture may cause diagnostic difficulties.…”

“…Chemotherapy is included if the stage of the cancer is advanced, unresectable and has positive tumor margins. Five-year disease-free survival rates range from 10% to 30% [9].…”