Radiation-induced synchronous mandibular osteosarcoma and papillary thyroid carcinoma: A disguised conundrum.

With substantial improvement in survival in cancer patients, the risk of radiation-induced malignancy in previously irradiated areas is increasingly possible. Both radiation-induced sarcomas and papillary thyroid carcinomas (PTCs) are well documented in literature. However, radiation-induced synchronous malignancies are rare, are often misdiagnosed, and presents with diagnostic and therapeutic challenges due to paucity of literature and lack of available guidelines. Here, we report a case of radiation-induced synchronous mandibular osteosarcoma and PTC in a previously treated carcinoma of base tongue with concurrent chemoradiation. He initially presented with an oral cavity mass, and during the course of the treatment was incidentally diagnosed with a synchronous PTC. It also establishes the indolent course of PTC, which often goes undiagnosed till the presentation with regional nodal metastasis. This report, to the best of our knowledge, is the first reported case of synchronous radiation-induced OSM and PTC.